Very common Water-line light fitting / housing found in many Signature, Designer, Leisurite, Lanark, Heritage, Four Winds Spas, Bullfrog Spas, Morgan Spas, Sunbelt Spas and other Spa Industries Spas. Also found in many Chinese imported spas. 

These often break due to over-tightening, and with age. Some manufacturers used the o-ring, and some did not.

Uses 12mm Hole. 17mm Face. Has ~6.8mm ID.

Note: As of 2023, some these fittings have 4 small ridges to 'lock' them in place when tightening them. They must be pressed in gently, but firmly. Also white nut is larger to provide more surface area to hold once tightened.

Light Wall Fitting, RD, MINI POL, 1/2"HS, 11/16"FD, CLEAR

Rising Dragon Pinnacle Light System
PST-57-850-1020
RD 631-1050