Sorry but I can't remember, it has been a couple of years. But if I remember correctly they come in different lengths, but easy to install.
Only problem I have with the spring is it will fall on your head if tripped. I have learned to be careful as all my boxes now have springs.
Just looked at the ones from west and they have changed "I don't like them" but if you google TH marine lid and hatch support springs you can find what you need. I like the ones with ss hardware not the molded plastic.
voyager