I have designed this fixture to hold my Astral Pool wall ducts (15663) in place in an appropriate cutout in the formwork block. After pouring concrete, the formwork adapter can be disassembled and reused. Since I concreted my pool in two steps, I only had to make 4 formwork adapters for a total of 8 wall penetrations.

For assembly, two planks are still needed as formwork, one has to be drilled with a 17 mm hole and one with a 59 mm hole. Furthermore, screws for fastening the formwork holder (e.g. 3.5 x 25 mm), an M16 screw, an M16 nut and a 2" locknut are needed.

Additional thread insert

The Thread_Insert_1_5zoll model is an alternative thread insert, for built-in parts with 1.5" thread.