SC757 or 40508 Darlly Hot Tub Filter 
Hot tub filter.
Length - 335 mm
Diameter - 127 mm 
Hole Top - HANDLE no hole
Bottom Hole 1 1/2'' Female Internal Thread (See Photos)
Description:
Compatible with Pleatco PWW50L, Unicel - 4CH-949, Filbur - FC-0172, Darlly - 40508  or SC757, Happy - HHTWW50L-R
Top Diameter 127mm, Filter Length 335mm, Top hole REMOVABLE HANDLE, Bottom Hole 1 1/2'' Female Internal Thread (See Photos)
High quality filter with Max-Flow Core and High Grade Filtration Media, designed specifically for Happy Hot Tubs. 
Removable top handle is compatible with the EZ-POD 
Compatible with the following filters: SpaChem O250 Pleatco PWW50L Unicel 4CH949 Filbur FC-0172 Darlly 40508 Used on: Arctic, Sunrise, Whitewater, Rising Dragon