I recently installed a 30 Metre Evolve retractible hose unit. I installed on a rough cut sand stone retaining wall as pictured. To keep the unit levelled in two planes requitred a few stainless steel washers to space the pivot block upright and level on the wall. (I assume that the requirement for a level installation is about the stop mechanism in the reel.) The unit works fine out of the box. Follow the instructions! Afeature of the pivot mount is that it allows the hose reel to swing into contact with the wall. Small pieces of rubber backed carpet fixed that.