Ultimate Discharge Tray
I just bought the new Rayspeed EXCEED Discharger from SpeedTech RC and I think it's the best tray available, especially for 3300s. The tray provides automatic cutoff (no more having to keep an eye on the lights to prevent too deep a discharge) and two separate discharge rates.
Some specs from SpeedTech:
Battery type: Sub-C NiMh, NiCD
Cells: 1,3,4, o4 6 cell
Mode: Equalizing (5 Amp discharge), Conditioning (1 Amp discharge)
Cut off voltage: Ni-MH (0.9V) NiCd: (0.1v)
Built in single fan
Led lights: Red = Power, Auto cut: yellow
Case size 161 x98 x47mm (which is about 6 1/2 inch x 4 inch x 2 inch)
It's a solidly built and compact unit and well worth the $56 price.