They ship two O rings, and I can buy them at a hardware store for a buck or two.

Dinotte appears to have simply unbeatable customer service. The owner/engineer there, Ray, answers email questions personally within hours, and I've never heard of anyone who ever had a problem with their response to a problem.

Heck, they will even upgrade old models with newer optics for a reasonable fee.

When most bike lights are disposable and not very good, it's nice to be able to buy something that's clearly designed to last a lifetime, and it's made in the US as well.