A great deal on a great jig.
When it was first invented, the inventor / friend of mine demonstrated his prototype to me, and I just had to have one, but I had to wait almost 5 months before they reached the stores. I paid a premium to get one from the early production, but it was worth every penny. I love that jig, and I threw about 8 shop made box joint jigs of various designs and sizes in the fire shortly after receiving it. Some made good joints and some were a little loose, but together they took up way too much storage space in my small shop. The I-Box jig replaced them all and takes up about 1/3 of the space. Plus, it's so easy to adjust for any width joint from 1/8" up to about 1". There are many ways to make box joints and I've tried many, but for me, this jig is the only way that I make them now.
The I-Box jig can be used on a router table, but I found that I can get better cuts using it on my table saw. A router bit cuts in both directions, so it really needs a sacrificial backer on both sides of the work to keep tear-out to a minimum. The I-Box jig has a backer for one side of the work included in the design, but you will need to attach a second backer to the face side of your work with double sided tape to get the best cuts with a router bit and you will need a new backer for the face side of every piece cut to get the same great results.
Pair the I-Box jig with your table saw and a Freud SBOX8 blade set or equivalent for 1/4" and 3/8" cuts, or a Freud LM72R008 or equivalent FTG type blade for 1/8" cuts and it makes some beautiful box joints. I rarely make box joints larger than 3/8", but have used my Freud SD608 Dado blade set for a few boxes and had good results too. They just don't have the perfectly square, flat bottomed cuts that these other blades can produce.
I know the inventor, but I have no other connection to him or Incra. I do like his I-Box jig though.
Charley