be affixed to a helmet with double sided adhesive tape preferably the flashlight body 20 includes a grip sleeve 87 around the outer surface of the body below the ring clip 70 in the preferred embodiment the gripping sleeve 87 is made of an elastomeric material and has a plurality of parallel ridges to facilitate gripping the flashlight 10 however the gripping sleeve 87 can also have a smooth surface referring now to fig1 the end cap 25 of the flashlight body 20 includes an integral mounting stem 30 that is hollow the mounting stem 30 has a stepped through bore for receiving a hollow vent plug 40 as seen in fig1 the hollow vent plug 40 includes a trilobal bore 42 through an inner wall thereof the trilobal bore 42 has a central bore 44 connecting three slots 42 extending through the inner wall of the hollow vent plug 40 and directed radially relative to the central bore 44 vent plug 40 also has an external wall 47 that is contoured to maintain the curvature of the surface of stem 30 a flapper valve 55 is disposed in the central bore 44 of the vent plug 40 and extends through the inner wall of vent plug 40 the hollow vent plug 40 has an open side 46 to facilitate insertion of the flapper valve 55 the vent plug.