LR-1/4-D-MINI G 1/4 Pneumatic Regulator 0.5bar to 12bar, LR-1/4-D-MINI. The Festo D series MINI size pressure regulator has a G1/4 pneumatic port connecting thread. It is a directly-controlled diaphragm regulator design structure with pressure gauge. The regulator has a working pressure up to 12 bar.