Keg spears for systems A, S, D, G and M Five systems. One standard for the beer path.

Turned, welded, electropolished, assembled in a clean room and leak tested. Parts in contact with beer are stainless steel, seals are EPDM.

Spears in detail Keg cross-section

AFlat spear

Range

The right spear for every keg

Flat spear
Round flange Ø 74.5
Bottom clearance 9 mmProduct page → S

Sankey spear
Tube lowers when opened
Bottom clearance 14 mmProduct page → D

Keg spear type D, threadless with retaining ring

Sankey spear (US Sankey), threadless
with retaining ring
Bottom clearance 14 mm
Also available with threadProduct page → G

Triangular spear
Triangular flange Ø 70
Bottom clearance 9 mmProduct page → M

Combi spear
Round flange Ø 74.5
Bottom clearance 15 mmProduct page →

Spear length

The right spear length

The H3 dimension runs from the sealing surface in the keg neck down to the sump in the keg. From it follow the overall length of the spear, which is used for ordering, and the length to the seal.

Keg

Size

System

Overall length TL568 mmH3 541 mm + 27 mm (system A)

Length to seal SL532 mmH3 541 mm − bottom clearance 9 mm (system A)

The overall length runs from the top of the spear to the end of the down tube. Spears are ordered by this length. In AOBAOSI drawings it is called TL (total length), the length to the seal SL (length till sealing edge). H3 values for DIN and Euro kegs are based on catalogue data from a European manufacturer. Depending on manufacturer and year of manufacture they differ by a few millimetres. To be sure, measure H3 on an empty, upright keg with a measuring rod through the keg neck.

Design

One valve or two.

From the outside the systems differ by the flange. What makes a spear work in service is inside: how many valves and how many springs it has.

A · G

One valve

One valve disc, one spring. The keg coupler pushes it open; gas and beer share one path, separated by the down tube and annular gap.

6 parts

S · D · M

Two valves

Separate valves for beer and CO₂, each with its own spring. The keg coupler opens both individually. The beer and gas paths are cleanly separated, and each valve closes with its own spring.

7 to 9 parts

Type	Design	Flange Ø	Seat	Body Ø	Opening Ø	Valves	Parts
A	Flat	74,5 ± 0,1	2″–14 TPI BS 84	48	35,7	1	6
S	Sankey	≈ 50,8 ²	2″–14 TPI BS 84	48,1	19,3	2	9
D	US Sankey	53,7 *	Locking lugs	50,2	38,9	2	8
G	Triangular	70 ± 0,1	2″–14 TPI BS 84	48	35,7	1	6
M	Combi	74,5 ± 0,1	2″–14 TPI BS 84	48	31,8	2	7

Dimensions in mm from the AOBAOSI assembly drawings. * On the D spear, measured across the locking lugs; there is no seated flange.

Keg cross-section · Cleaning and dispensing

Too long. Too short. See what it does inside the keg.

Keg, keg neck, spear and down tube come from the original STEP files (DIN 30 and DIN 50 with flat spear, S Sankey spear from DIN 30, extended to the keg height for DIN 50), turned and cut open by a quarter. We show the M spear with the geometry of the flat spear and the clearances of the M system. Set the down tube too long, correct or too short, and run the cleaning cycle or dispense the keg empty.

Cut-open stainless steel keg with spear and down tube

Magnifier · Sump

Sump

Down tube

Spear in the keg neck

Filling and cleaning head (schematic)

—

Geometry from CAD, flow shown schematically.

System	too long	correct	too short
A, G	3 mm	9 mm	15 mm
S, D	8 mm	14 mm	20 mm
M	9 mm	15 mm	21 mm

A spear of the wrong length looks like any other from the outside. What it does shows only inside the keg: in cleaning and when dispensing. On S, D and M the bottom clearance is fixed: 14 mm on S and D, 15 mm on M. When the dispensing, filling or cleaning head opens the valves, the down tube moves down by the valve stroke, about 7 mm during cleaning. The distance to the sump then becomes correspondingly smaller. If the tube is too long, it touches the bottom.

Cleaning steps and limits according to Brewers Association (“A Practical Approach to Refillable Kegs”), schanksysteme24 and ProBrewer, compiled by Keg Exchange. Values vary from system to system.

Marking

Two marks you can read on the keg

Type A spear from above, triangle and line

unlocked

Safety triangle

After installation, one tip of the black triangle must point exactly at the line on the spear body. The safety lock is then locked. If it points to one side, the keg is not filled. Applies to A, G and M. The model shows type A based on the design data; the laser marking replicates the current series part.

Head of an AOBAOSI type A spear from above, laser marking on flange and seal

Year on the seal

The year of manufacture is laser-marked into the seal, on this spear 25 for 2025. The number can also be read from outside when installed, so you can see at the keg straight away when the seal needs replacing. The flange carries the logo, date code and the SK mark SK 448-005 from DGUV Test certificate NV 24816.

From the Lishui plant

How a spear is made.

Pictures from opening day, 30 September 2026. Assembly in the clean room, rotary indexing machine, testing and assembly stations.

Rotary indexing machine, final assembly

Assembly line in the clean room

Wire basket with individual parts for spears — Individual parts in a wire basket

Assembly station with workpiece carriers

Machine with compressed air supply

Type A spear taken apart into its components — Type A spear, all components

Laser processing of the stainless steel tube — Laser processing of the tube

CNC lathe with wire mesh boxes full of turned parts — CNC machining of the turned parts

System comparison

Keg spears A, G, M, S and D compared

The spear, also called an extractor or, in the standard, a container connection part, is the closure of the keg. Kegs are cleaned, filled and dispensed through the spear. Five systems are common: flat spears (A, G, M) with a flange and Sankey spears (S, D) without a flange. Each system has a matching keg coupler.

System	Design	Flange	Valves	Bottom clearance	Keg coupler	SK
Type A	Flat spear	round, Ø 74.5 mm	1	9 mm	A system	SK 448-005
Type G	Triangular spear	triangular, Ø 70 mm	1	9 mm	G system	SK 448-005
Type M	Combi spear	round, Ø 74.5 mm	2	15 mm	M system	SK 448-005
Type S	EU Sankey spear	no flange	2	14 mm	S system	SK 448-002
Type D	Type D Sankey spear (US Sankey)	no flange	2	14 mm	D system	SK 448-002

Thread of all threaded spears: 2″–14 TPI to BS 84. Parts in contact with beer are AISI 304 stainless steel, seals are EPDM.

Frequently asked questions

What workshops want to know

Do AOBAOSI spears fit every keg neck?

Keg spears with a thread have 2″–14 TPI to BS 84 and therefore fit standard keg necks. The D spear is threadless in its standard version and is held in the keg by a retaining ring. A version with a 2″–14 TPI BS 84 external thread is also available.

What torque is used to tighten a spear?

Type A and G: 80 ± 5 Nm, applied evenly without jerking. Empty returned kegs are retightened to 60 Nm before refilling, never under pressure. The same values apply to S, M and the D spear with external thread: 80 ± 5 Nm for installation, 60 Nm for retightening.

Which keg couplers fit?

Each spear works with the keg coupler of its system: A with A, S with S and so on. AOBAOSI supplies keg couplers for all five systems.

How do I get the right length?

With the inner height H3 of your keg and the bottom clearance of the system. Tell us both and we will supply the spear in the right length.