Ronstan "Shocks". A sheaveless block made from aluminium anodized in either blue or silver. Sold in pairs (Need 2 packs for the D-Zero Control Line upgrade) At a mere 2.5g (0.1 oz), SHOCKS are outstanding performers in the strength and weight stakes. The clever design and exacting finishing also provide excellent free running at moderate changes of angle. Permitted for use in the 2020 Class Rules for D-Zero as control line assistance.