ITEM NAME:10x suction cup Ø 40mm with M4 thread, suction cups, with knurled nut clear FT And clear knurled nut. Suction cups transparent, diameter 40 mm, For fixing signs etc. on smoo th Surfaces, such. Glass, tiles, etc. M4 threaded pin with 6 mm length. The suction cups are made with a high quality, transparent.And clear knurled nut. M4 threaded pin with 6 mm length. Knurled nut supplied (no simple, soft "whites").