Those who keep up with eBay have seen these inexpensive plastic trombones. My back is sore, and I thought holding up a lighter horn would let me practice more. So I bought one. Interesting bone. The slide is plastic on plastic. No oil, trombotine, etc. Soapy water is used as a lubricant. I thought the tone would be awful -- but to my surprise if you throw out the plastic mouthpiece and put in a good mouthpiece, the tone was fair. My thought is it could be used to beginners. But in the US, bands play for US Football games - sometimes in the very cold and snow. Most buy cheap $50 bones to play in pep band and or to march with. The plastic bone might work well for that kind of work. There is a problem with a self-test. You tend to hear things the way you THINK it should sound. Very hard to be objective -- you need a brass player you trust to listen to how it sounds. Anyone one else have thoughts? I have not tried putting the slide on a different horn. The slide is very light and smooth and the bell is the most important sound part of any bone.