The difference between 15A and 15B is that. 15B is with aviation potentiometer material.Universal 15 Amp 1/2 wave self excitedDip-SwitchProgmmable avrVoltage regulation Less than 1%;220 / 440VAC programmable inputRugged compact design;Starting tension mechanized on ramp;With protection under frequency rollEMI Suppression;15Amp high capacity integrated fuseVoltage: 220 / 400VAC 1 Phase 2 ofPower input voltage: 180-240VAC 1 Phase 2 ofOutput voltage: Max 90 VDC at 240VAC inputCurrent: Continuous 6A, intermittent 12A for 10 secsResistance: Min.10 ohm, maximum 100ohmBuild voltage-: Residual voltage in terminal avr more than the 5VACVoltage regulation: Less than 0. 5% with 4% engineOperating temperature: - 40 Celsius to + 65 CelsiusStorage Temperature: - 40 Celsius to + 85 CelsiusExternal volts Adjutment: 7% with 1k ohm 1 watt trimmerEMI suppression: Internal electromagnetic filtering interferencePower dissipation unit: Max. 8 wattOften protection: 60Hz system preset knee point to 57Hz / 50Hz system preset knee point to 47HzColour:BlackMaterial:plasticPackage Contents:1*Generator accessoriesOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.