Re: TELMA unit for sale
IIRC, the Telma retarder is an "engine brake". It's actually a high current generator mounted between the transmission and driveline. The generated current, which is made from the vehicle's momentum, is converted to heat energy by a large resistor. So the bus is slowed by heating air, as opposed to the brakes, which by friction heat the brake drum/disk (& then air). Or something like that.
From my research, it's the best "engine brake" for a Cat3208, and in the case of my Cat3208na, the only "engine brake" that won't break the engine.
Ah, how much you want for it?