The tree piece Initiation Kit from Rascal Toys is harness compatible or as stand alone pieces. The small dong is 4.25 x 1, the medium dong is 6 x 1.25, and the large dong is 7.25 x 1.5 and each comes with a suction base for a secure grip and hands-free fun. Made of comfortable and durable SensaFirm, each dong is easy to clean and super slippery when lubricated.