SIS GO Isotonic Energy Gels Multipack (6x60ml) When you need a fast, convenient energy boost. SIS have designed the world's first isotonic energy gel to be clean in the mouth and easy to digest. Their patented product means it delivers energy fast without the need for extra water. Winner of the Queen's Award for Enterprise, this innovative product continues to be seen at the forefront by endurance athletes. Use during endurance sessions and events to help avoid flagging.