RENNtech ECU Hand Held Tuner (HHT) for CLK 63 AMG BS (C209- 534 HP / 485 LB-FT)RENNtech ECU HHT (HandHeldTuner) for the 209 CLK 63 AMG Black Series. Up to 534 HP and 485 LB FT LB FT. Gains: +34 HP & +20 LB FT. RENNtech HHT (hand held tuner) allows you the unlimited ability to switch between tuned and stock ECU programming and requires no ECU removal! Our proprietary tuning module stores both the RENNtech tuned file and your vehicles stock file. The module plugs directly into the OBD2 port and delivers the file you choose