£4.60 Entonox® Clear-guard Midi Breathing Filter £68.00 Pack of 35 Straight Entonox® Mouthpieces £445.00 Entonox® Basic Pain Relief System without Case £6.00 Pin Index Flat Key (economy) - Plastic £150.00 Bullnose Oxygen Regulator with Multiflow Valve for F Size Cylinders £102.00 Select-a-Flow Meter with BS Probe