Manufacturer part #: 1200. 
Strong. Durable. Gentle. Harken Protexit blocks protect the race results you work hard to achieve. All-aluminum, wear-resistant housing carefully ushers line in and out no matter the angle.
Technical Description
     Protexti Single Exit Block
  1 3/16 in
 30 mm
  2 15/16 in
 75 mm
  1.3 oz
 37 g
  5/16 in
 8 mm
  #10 FH in
 5 FH mm
  2 1/4 in
 57 mm
  550 lb
 250 kg
  1103 lb
 500 kg
 
When you race HARD, and you rip through as many hoists and douses as we do sailing W-L legs all the time, you should expect to start wearing through the sideplates of your halyard exit block right? Wrong! Thanks to Harken Protexit™ blocks, wear from side angle loading is not inevitable. Protexit’s all-aluminum, wear-resistant housing carefully ushers line in and out no matter the angle. There’s more: Protexit blocks offer higher working loads than any small boat exit blocks we’ve ever made. Protexit aluminum sheaves rotate on sleeve bearings with Delrin® sideload balls so they don’t deform in extreme conditions, while reducing wear on the halyard, too.