4UAD Smart Airsoft's ASMR episode shows an Arcturus Airsoft PP19-01 AEG that has been upgraded with Zenitco parts externally and a Perun Airsoft ETU internally. The process begins with the unboxing of the PP19. The PP19 is then carefully taken apart to expose the gearbox. The sensor is tested to ensure it's functioning properly before the gear shimming process begins. The piston is installed with precision, after which the box is securely closed. The Perun ETU is then set up. Following this, the Zenitco Stock is installed. The rail and barrel assembly is carried out meticulously. After all the components have been assembled, a final test is conducted to ensure everything is working as expected. The process concludes with a mag dump.