Based on this product's specifications, here are some alternatives and similar models
StarTech.com LC Loopback Plug Single Mode 9/125 LC Fiber Loopback Adapter LC/UPC Connector
Summary description:
StarTech.com single mode 9/125 LC fiber loopback adapter featuring an LC/UPC connector for network testing and troubleshooting. Designed for fiber optic testing applications, this loopback plug provides a stable optical return path to test network transmission performance in data centers, telecommunications, and local area networks efficiently.