Trumpet pistons are made out of multiple different materials some better than the other. Trumpet pistons can be made out of three materials.
1. Nickel- Is made out of nickle. It is found on the lower costing trumpets. It is more prone to flaking and does not last as long.
2. Monel- Is made of both nickel and copper allow. It is a very hard material and better than nickel.
3. Stainless Steel- Is the most popular choice for intermediate to advance models. It contains chrome and nickel. It is solid and not subject to flaking.
Both the TR-330 and the TR-430 are made out of stainless steel. This is another reason why Jean Paul USA goes against the majority of the companies by offering things found on professional instruments but at a much more cost effective price.