Are these any good? They seem a little on the cheap side.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0171839589
These are more expensive but look like exactly the same thing.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0171851384
Do the check valve of this type actually work well? I'm hoping someone here actually has experience of one of these.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0171839589
These are more expensive but look like exactly the same thing.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0171851384
Do the check valve of this type actually work well? I'm hoping someone here actually has experience of one of these.