The difference between 15A and 15B is that 15B includes aviation potentiometer material. Universal 15 Amp 1/2 wave self-excited Dip-Switch programmable AVR. Voltage regulation less than 1%; 220 / 440VAC programmable input. Rugged compact design; starting tension mechanized on ramp; includes protection under frequency roll. EMI suppression; 15Amp high capacity integrated fuse. Voltage: 220 / 400VAC, 1 Phase. Power input voltage: 180-240VAC, 1 Phase. Output voltage: Max 90 at 240VAC input. Current: Continuous 6A, intermittent 12A for 10 seconds. Resistance: Minimum 10 ohm, maximum 100 ohm. Build voltage: Residual voltage at AVR terminal more than 5VAC. Voltage regulation: Less than 0.5% with 4% engine. Operating temperature: -40C to +65C. Storage temperature: -40C to +85C. External voltage adjustment: 7% with 1k ohm 1 watt trimmer. EMI suppression: Internal electromagnetic filtering to reduce interference. Power dissipation unit: Maximum 8 watts. Frequency protection: 60Hz system preset knee point to 57Hz; 50Hz system preset knee point to 47Hz. Color: Black. Material: Plastic. Package Contents: 1 x Generator accessory Only the above package content, other products are not included. Note: Lighting and different displays may cause the color of the item in the picture to vary slightly from the real thing. Measurement allowance is +/- 1-3cm.