I agree with JeramyK. I've used the below seperator in the past in a pinch, but a press works much better. It will damage your string the more you use it, even though it says it will not.

Another good option such as Cat Whiskers are BowJax in the original model. They slip over your string without a press and are held on by very tiny cable ties. It sounds clunky but it isn't. I used them for years before I put on a STS and liked them way more than the leeches, and I still use them on my back-up bow.





BowJax: