The old MTD valve core corroded and broke off inside the valve stem when trying to remove it. This TR412 valve stem was an exact replacement and was easy to install. As I only needed one I just wish they were cheaper and/or cheaper in a 2 pack.
Pros
High quality: made of brass and synthetic EPDM rubber. These valve stems withstand a wider temperature range than natural rubber stems and remain flexible even in the coldest weather.