Fits select Waterway Jets, check your manual to ensure proper fit. This part# 218-6930B is the same as 218-6930 except this part is in mfg. sealed packaging. This diffuser has the part number 218-6930 stamped on it. This Waterway part is thin and fragile so great care must be used in installation. Waterway Diffuser Mini Storm Part # 218-6930B. This Waterway part is thin and fragile so great care must be used in installation. If your installer is unfamiliar with the installation, then contact the mfg. Waterways or your spa mfg. for tech support.