This set is exactly what is need if you're building 2 channels of the the F5 Turbo V2 (pair of 50W Monoblocs or 50WPC Stereo) or if you're repairing the power amp section of a Ampeg SVT 3 Pro, SVT 450H, BR1E, or BR2E. 

4 pcs Precision 0.1% Matched IRFP240 MOSFETs 

4 pcs Precision 0.1% Matched IRFP9240 MOSFETs 

MOSFETs are manufactured by Vishay, IR, and/or Fairchild. 

 MOSFET Vgs is measured at 170mA in a steady temperature room and with a timer circuit for consistent and precise matching.Each set is matched within +/- 5mV (0.1%). Often even closer. 

 See other listings or inquire for other quantities. Pairs, Triples, Quads, Sextets, Octets, etc.