Marquis Spa light lens bullet. This is the light holder for select Constellation Marquis spa lighting systems.

This part is the LENS.  You may also need the nut - sold separately - see 740-0686.

Lens measures just under 1” diameter (15/16” to be exact). The hole in the spa wall should be 3/8”.

Marquis Spa Light Lens Bullet 740-0683

(image currently unavailable, but if you were referred to this sku, it is the right part for your Marquis Spa.)