Features:
Compatible with most bottles
Built-in 0.5Mpa pressure gauge
Built- in 0.3Mpa auto relief valve
Use with ??4 tube
 
Size Chart:
Height/Width/Length:  80 x 15 x 35 mm (3.15   x 0.59 x 1.38 inch)
 
Part List:
1 x Bottle Cap with Relief Valve and Pressure Gauge