I have installed these on my daysailer after removing the cheek blocks at the base of the mast. With these cam cleats you can get the halyard tension you want instead of loosing tension tying the halyards off on cleats. The ease in which you release the halyards and drop the sails is also a big plus. The pivoting base is also great for pulling from different angles. All in all a great upgrade for the Daysailer. Harken Big Bullet Exit Block with #150 Cam Cleat Description Pivoting exit/cam Sheave dia. (in) 1-1/2 Length (in) 3-1/8 Weight (oz) 8 Max. line dia. (in) 3/8 SWL (lb) 300 Breaking strength (lb) 2000 Installs with 2 rivets or bolts. Availability: Usually ships the next business day. Harken #140 Big Bullet Block with Cam Cleat for DS Halyards H140Regular price: $91.65Sale price: $77.99 Due to the wide variety of the size and weight of our items we will charge the actual cost of shipping in a separate charge on all orders. Please email us for a shipping cost estimate. Shipments outside the USA may have add on fees and duties by your own government. Sailing can be green! See our recycle your old sail offer Send us email