A holster that lets you keep your trusty calipers by your side all the time. Meant for the 4" Harbor Freight Digital Calipers: http://www.harborfreight.com/4-inch-digital-caliper-47256.html After wearing this for a day I found it was necessary to round the corners on the top with a file to make it more comfortable. I might make a second revision someday that fixes this.