Wyhaq reviews the 5KU Airsoft Shadow 2 blowback unit, comparing it to the premium CL Project unit and the heavy stock component. According to him, the 5KU unit is made of 60 series aluminum, is very inexpensive at $10 and weighs just 8g, matching the weight of the $50 CL Project unit (70 series aluminum). Both aluminum options offer a significant weight reduction from the 28g stock pot metal unit.

After installation, the reviewer discovers a critical durability flaw in the budget part. The 5KU unit's 60 series aluminum proved to be excessively flexible and "super bendy" compared to the solid construction of the CL Project unit. He says that the CL Project's superior 70 series aluminum construction justifies its higher price for the necessary structural integrity.

A final issue arose when attempting to install the 5KU unit into a stock slide, where it was found to be incompatible due to a differing curve. Given the low durability and the critical incompatibility with the stock slide, Wyhaq advises viewers against purchasing the 5KU blowback unit, especially if they intend to use it as a budget upgrade with the original slide.