SAILSetc design and manufacture. A beautifully simple design of block - simply designed better - that allows real versatility in use. The sheave is a stainless steel ball race and the block has the lowest friction of all the similar items we have tested. This is the smaller of two otherwise identical items but has enough strength for radio yachts up to Ten Rater size. Suitable for Dyneema line from 10 kg up to 75 kg breaking strain. It can be dismantled and maintained with no danger to the bearing. This block can be used in two principal ways. One way is by suspending it on a line of Dyneema or Dacron. The other way is to fix it to a surface using bolts or screws. Each block is supplied with fasteners.