Budget anti-heat stainless steel cylinder from XT.  The vents are 51mm from the cylinder end.  Machining is pretty decent with no reported burrs on the vents however I recommend checking and if so sanding them down, this will help preserve the piston head o-ring.  The inside surface has been plasma polished.

Specifications
Material: Stainless steel
Vents: 4 (51mm distance of the vent to the cylinder head end)
Internal Diameter: 23.7mm
Outer Diameter: 25.4mm
Length: 72mm
Weight: 24g
Recommended Barrel Length: 350mm - 380mm

Cylinder Size Guide