Optimus Prime's Stereo Equipment Old School Audio - Old School Prices - Professionally Tested Product Description This is a Sony SA-WM20 active (powered) subwoofer, magnetically shielded, as read from the rear panel label. The unit powers on and produces bass output, with the built-in amplifier, RCA line-level input, and spring-clip speaker pass-through terminals all confirmed working. Cosmetic condition is good with light scuffs and surface marks consistent with normal use. Please review all photos for details. Highlights At A Glance ✔ Fully tested and verified ✔ Good cosmetic condition with light scuffs and surface marks from normal use ✔ Fast, insured shipping, carefully packaged Testing & Verification The internal amplifier was exercised at volume and confirmed producing clean, distortion-free bass output. The RCA line-level input was tested with a signal source, and the spring-clip speaker pass-through terminals were checked for solid connection and continuity. No rattles, no hum, and no abnormal noise were detected during testing. Shipping Fast, insured shipping from Minnesota. Item is carefully packaged for safe delivery.