The Zalman 8800 blocks have swivel barb fitting that is made for 8mm (5/16") ID tubing. The fittings can come out but they are not BSP. Aqua Computer has 8800 blocks that are G1/8 and you can put a 3/8" barb in those. The Danger Den blocks are G1/4 and can also be used with 3/8" or 1/2" barbs. I...