I too have the Spigen Rugged Armor case, combined with the separate Encased Belt Clip holster: https://www.amazon.com/gp/product/B01N02W6T7

It's a magical combination! The case is very protective, but perfectly thin. It's my favorite case of any phone that I've owned.

The Encased bolt clip holster is awesome too. I've been using belt clip holsters since my Moto Razor phones, and they all stunk until this one. The rotating assembly would always break, or the retention clip didn't work right. Encased doesn't have these problems.

I finally broke a part on my holster last month, when I rammed into a hard wall that caught the top of the clip that holds the phone in the holster. Luckily, they have a lifetime warranty and they sent me a new holster for free!