TKR6514HD Tekno RC Differential Outdrives (f/r/c, HD, EB410/ET410). Our new heavy-duty outdrives retain the same physical dimensions as our standard EB410 and ET410 outdrives (TKR6514) but have less material removed for improved durability and impact resistance. These new outdrives are recommended if you are running in harsh conditions. For all of the ET410 owners out there looking to run larger 1/10th monster truck tires, these are a must! The HD outdrives are also ideal for carpet racing with frequent on-power jump landings. They are made from the same material and are a direct replacement for TKR6514.