I've had 2 pyle 21" subs laying around the house i bought for $30 off my friend he had them sitting in his house for a long time. Just for fun i put them in my van on a Kicker KX2500. The subs surprised the hell out of me they get nasty for what they are. I'm going to keep them in for a week ot so to see what kind of beating they can take till they blow. Anyone ever used these before? Ha!