This is an Assortment of 4mm diameter Flat Head Self Tapping Screws from DuraTrax. Plain Black metal construction All with a flat head and a phillips recess drive insert 5 each of the following lengths included: 15mm 20mm 25mm The threads on the screw are coarse and designed to dig into the the nylon that they are screwed into, which keeps the connection tight. Comes in a zip-lock bag for convenient storage (15) Screws #1 Phillips Screwdriver bmb 8/9/00 ir/jl kr3/10/03 updt jxs 4/13/04 &