Here's what Cioks say about the 6030 Flex Battery Snap:
Type 6 Flex cables are black and fitted with a 9V battery snap or clip if you like. This Flex cable should be used with 9V battery powered pedals which don’t have an adapter input socket e.g. vintage Wah pedals or some MXR or Roger Meyer fuzz pedals. This Flex cable is available in two cable lengths 30 or 50cm.