The Harken 29 mm Zircon Triple Block, part number 2189, can handle a maximum working load of 240 kg (525 lb) and has a maximum line diameter of 6 mm (1/4 in). With a sheave diameter of 29 mm (1 1/8 in), the newest addition to the Zircon lineup features six models, expanding the total options from eight to eighteen. Zircon is not a universal solution - no block is - but these smaller sizes are suitable for control lines that require multiple purchases. Zircon reacts quickly, making it ideal for situations where immediate response is necessary, such as when easing the 24:1 Cunningham rigged under the deck or adjusting the jib lead for more power in choppy conditions.