This model is discontinued
AirTAC has phased out the MAL series. The drop-in replacement is B04-SAI50X125S — same bore, stroke, output force, port and mounting, so it fits the same application. Simply order the B04-SAI50X125S in place of this model. The SAI replacement keeps the same ISO 15552 mounting interface, bore, stroke, output force and accessories, so it drops straight into existing fixtures. It is the current-production version of this cylinder with an upgraded piston seal.
Airtac B04-SI Construction Machinery Special ISO Standard Cylinder B04-SI50X125S
The AirTAC Airtac B04-SI Construction Machinery Special ISO Standard Cylinder B04-SI50X125S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 125mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the drop-in replacement is the B04-SAI50X125S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke125 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → B04-SAI50X125S
About the Airtac B04-SI Construction Machinery Special ISO Standard Cylinder B04-SI50X125S
The AirTAC B04-SI50X125S is a discontinued double-acting ISO 15552 profile cylinder delivering 982 N push force at 0.5 MPa. The B04- prefix marks this as AirTAC's construction-machinery dedicated variant, mechanically identical to the base SI50X125S with a 125 mm stroke, G1/4 port, and M16x1.5 rod thread. As this legacy line is end-of-life, AirTAC replaced it with the exact drop-in SAI50X125S.
The SAI50X125S shares the same ISO 15552 mounting interface, bore, and force, fitting existing fixtures perfectly. It upgrades the piston seal to two Y-shaped one-way elements for lower start-up pressure and longer life. For your sizing, the safe working load is roughly 589 N (60% of the 982 N push force), equating to a 50 kg vertical lift with a 2:1 margin. The -S magnet supports legacy CS1-B/DS1-B sensors, while the SAI family adds SAIL, SAIF, and BSAI lock variants the SI lacked.
Airtac B04-SI Construction Machinery Special ISO Standard Cylinder B04-SI50X125S Technical Specifications
| Model | Airtac B04-SI Construction Machinery Special ISO Standard Cylinder B04-SI50X125S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | B04-SAI50X125S |
| Bore size | Ø50 mm |
| Stroke | 125 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M16×1.5 |
| Fluid | Air (filtered by 40µm element) |
|---|---|
| Operating pressure | 0.15 – 1.0 MPa |
| Proof pressure | 1.5 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 800 mm/s |
| Cushion | Adjustable, 30 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The B04-SAI50X125S carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø50mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 982 N | 825 N |
| 0.7 MPa | 1374 N | — |
| Max (@1.0 MPa) | 200 kgf | |
The B04-SAI50X125S produces the same force from the same bore — a true drop-in on output. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac B04-SI Construction Machinery Special ISO Standard Cylinder B04-SI50X125S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×125 | Stroke length in mm. |
| -S | Optional built-in magnet for sensor position sensing. |
Legacy SI-family variants: SID (double rod), SIJ (adjustable stroke) — each maps to its SAI equivalent (SID→SAID, SIJ→SAIJ). Rod material: carbon steel (blank) / SUS420J2 (A) / SUS304 (B).
Where the Airtac B04-SI Construction Machinery Special ISO Standard Cylinder B04-SI50X125S Is Used
Excavator Door Latches
Actuates heavy cab door mechanisms on earthmoving equipment, utilizing the 982 N push force to securely lock and release structural panels.
Loader Arm Stops
Provides reliable mechanical positioning for articulated loader arms, with the 125 mm stroke offering precise movement for heavy-duty tooling changes.
Crane Outrigger Pins
Drives safety locking pins on mobile crane outriggers, where the 50 kg vertical lift capacity with a 2:1 margin ensures positive engagement.
Replacing the Airtac B04-SI Construction Machinery Special ISO Standard Cylinder B04-SI50X125S with the B04-SAI50X125S
To replace the discontinued B04-SI50X125S, order the SAI50X125S. Confirm the ISO 15552 mounting interface, 50 mm bore, 125 mm stroke, G1/4 port (PT/G/NPT), and mounting accessory. The -S suffix means a piston magnet for CS1-B/DS1-B switches is present; the SAI uses current AirTAC switches. If sizing up or down, neighboring bores are 40 mm (628 N push @0.5 MPa) and 63 mm (1559 N push @0.5 MPa). A plain cylinder drifts on air loss—the cushion only decelerates—so for load holding use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. At 125 mm stroke, rod bending is low, but always guide side loads.
Replacement checklist
- ✓ Same ISO 15552 interface → B04-SAI50X125S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac B04-SI Construction Machinery Special ISO Standard Cylinder B04-SI50X125S FAQ
Yes, the B04-SI50X125S (the construction-machinery dedicated variant of SI50X125S) is discontinued. The exact drop-in replacement is the SAI50X125S. It shares the same ISO 15552 mounting interface, 50 mm bore, 125 mm stroke, force, and G1/4 port, fitting existing fixtures without modification.
This double-acting cylinder has a G1/4 air port. The thrust ratings are: 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, 1767 N push at 0.9 MPa, and a theoretical maximum of 200 kgf at 1.0 MPa. Operating speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
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