Just a leather belt. I got it as a "conceal carry belt"...but its just a plain ol' black leather Amish-made belt.
My holster is an Alien Gear cloak tuck, 2.0 I believe. Leather base panel, plastic belt clips with 3 adjustment points on each clip to set ride height and cant. My shell is a homemade custom kydex shell, I molded it around my personal Hellcat because I have an O-light Baldr Mini laser/tac light and nobody made a shell for it. I just molded the shell, and trimmed it to fit the 4 Alien mounting screws.
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The photo shows it attached to my cloak tuck 3.5 baseplate - same shape as the 2.0 but made out of thin stainless covered in neoprene. Good for standing, but the lower edge does pinch and poke a bit when seated or bent at the waist, so I swapped it over to the leather base and have been thrilled.