Extremely powerful: Our special manufacturing process allows our suction cups with knurled nut an incomparably strong and durable hold on smooth surfaces such as fluids, windows and walls or outdoors or in the bathroom Easy to install: No drilling, no screws, simply clean the surface, press and fix with a knurled nut. Product details: 20 large suction cups. The actual size of the suction cup is 40 mm. Each cup can hold up to 2 kg. Versatile: Our suction cups can be sucked on all smooth surfaces such as windows and glass, ceramic tiles, plastic, etc. Pack of 20 suction cups with 40 mm M4 thread - transparent suction knobs with knurled nut. Thanks to the vacuum effect, they have a high suction power and are suitable for fixing: + hanging signs of all kinds: office signs, bus signs, advertising posters + in the motorhome: for fixing light objects + in the kitchen or bathroom: as a towel holder, for fixing a soap dish in the shower cubicle. Your advantages at a glance: Extremely versatile. Unparalleled hold Very high absorption capacity. Quick and easy assembly.Yeuri