This our Gnarwhal 2.5 reservoir mounts made to weld to a flat surface, such as a side of a frame rail etc. only made to fit a 2.5 reservoir. Sold in sets of 4, takes 2 clamps per resi. Hardware included 1/4-20. All resi mounts should be installed by a professional or qualified installer. Please allow 24-48hrs for shipment excluding holidays and weekends. all orders are made to order