It makes the handstall 5 loops instead of 6. The 1799 is known as a wide and deep pattern but some people find their hands slide a little side to side in the handstall. The 5 loop mod is punching an additional hole in the wrist section and lacing through it, this makes the hand stall 5 loops wide as opposed to the stock 6. The mod can be easily undone and reverted back However you will see the punched hole.