According to the manufacturer that speaker has a maximum input power of 210 watts. It has a suitable amplifier range of 15-300 watts. I think this is why you're looking for a mono block amplifier with 300 watts. Those numbers are a little confusing. The truth is that speaker will never use 300 watts. If you really want a mono block for that speaker I think a 200 watt mono block would be plenty of power. With peaks a 200 watt mono block will usually make more power. Here are a couple of mono blocks that would work.