It's a little screw adapter thingy. WHY GET THIS PRODUCT: If you have some sort of mic stand or boom arm that has a small screw but your microphone has a big screw, this is the adapter for you. Product Dimensions : H 12.5 x D 18 mm; 32 Grams. 5/8 inch Male to 3/8 inch Female Knurled Mic Screw Adapter. A thread adapter to attach a microphone to a microphone stand. It features 5/8” male to 3/8” female for use with mic stands with European 3/8” threads. Knurled outer flange for ease of tightening. Great little piece of equipment to own for any photographer or videographer, great adapter to attach Blue Snowball Mic Blue Yeti Microphone to the Microphone Suspension Boom Scissor Arm Stand. Note: Most mics have a 5/8 thread. The diameter of a 5/8 threaded hole is about 15mm. You can check it before purchase. Note: It doesn't work with Blue Yeti Nano since the bottom screw hole of Yeti Nano is 1/4-20 threads. Package includes: 2 x 5/8" Male to 3/8" Female Screw Nut