I created these holders to integrate LED lights into my BestWay pool, I wanted them to be easy to assemble and disassemble, so I used the inlets and outlets of the recirculation pump. Simply unscrew the fitting and insert the holder with the hollow part first, then screw it back on. The lamps I used have an outer diameter of 70 mm and fit in with slight pressure, however, with a slight force they can be extracted to change batteries or recharge. The model to be mounted on the water outlet has 4 small fins to ensure that it remains well centered in the ring, the suction one I preferred not to make the fins so it also fits also to the skimmer ring which is generally larger. I bought the lamps on Aliexpress.