Flex, length, and girth. The flex depends on the company and the flex they make it as. I've seen 65, 67, 70, 75 so it depends (if you want int. flex but senior dimensions, Bauer makes 77 senior flexes). And if your a beginner....I'd recommend trying some wood sticks to find what flex you want as going from int. to a senior is pretty noticeable and you might not like it. It'll be a few inches shorter, usually like 3-4" but that's not a problem for me personally cause I usually cut normal length sticks that much. And lastly, there's the girth, intermediates feel slightly thinner than a normal senior.