This pack of 10 Amflo C20-23 I/M Design Steel Couplers features a 1/4 inch quick connect and a 3/8 inch FNPT. These couplers are designed for easy and efficient use with various air tools. The Amflo brand is known for its high-quality products and this pack is no exception. The couplers are durable and reliable, making them a great addition to any workshop or job site.