These clips are used to hang pieces of 1/2" Metal EMT from your gutters. Most commonly, the EMT is used for attaching products such as Boscoyo's ChromaTrim for pixel mounting. The EMT gives the ChromaTrim a secure location to be attached to. The clips are CNC cut out of 3/8" Marine Grade HDPE which is both UV stable as well as temperature resistant. The number of clips needed is dependent on the span, because EMT is fairly rigid, 3 clips should be more than sufficient for a 10 span. Simply attach the clips to the EMT and hook on to the gutters. The combined weight of the EMT, ChromaTrim and lights is enough to keep them stable even at high winds.