Introducing the newest additions to the Harken Zircon family, the 29 mm Zircon Double Block, also known as Part No. 2187. These innovative blocks have a maximum working load of 160 kg (350 lb) and a maximum line diameter of 6 mm (1/4 in). The Zircon line now offers a total of 18 models, including these six new ones with 29 mm sheave diameters. While no block can be considered all-purpose, these smaller sizes are perfect for control lines where multiple purchases are needed. With its immediate response, the Zircon is your go-to block when you need to ease pressure on that 24:1 Cunningham rigged under the deck or when you want to adjust the jib lead for more power through the chop.