Longacre No. 50100 TIRELIEF Kit. Kit is all there and includes 4 more Tireliefs ($55 value)  for a total of 10 Tireliefs.

LONGACRE 50100

TIRELIEFS™ Tire Pressure Relief Valves

  

Relieves tire pressure buildup as you race - automatically.

Use with quick change adapters or mount directly in your wheels by drilling a 1/8" NPT thread hole.

3-40 psi range

100 mesh inlet filter - to keep dirt inside tire from plugging TIRELIEF™

Lightweight aluminum - only 9 grams - won't affect wheel balance

Pro-Team TIRELIEF™ Kit

Preset your TIRELIEFS™ BEFORE you install them in the wheels. The setting tool uses your compressed air supply to accurately simulate tire pressure to set valves precisely.