I named mine Bob but if you ask one of those people behind the counter at Hobby People they know them as landing gear blocks.OOOORRR you can make up your own like I do. A table saw blade is 1/8 inch wide, Ripppppp, move the guide over a bit and RIPPPPPPP. You can make your own with any number of wire widths and depths. I make it up in several feet lengths and cut as needed. A Table Saw is your friend.
Your going to ask what kind of wood I use aren't you?? Well, I go into the corner of the wood shop where there is a lot of scrap wood and look for any hardwood that I think is light enough. Red Oak is always in the corner but not the best thing to use. I don't care what make and model of wood it is as long as it will do the job. If I'm cutting the blocks for a wing that has an angle to it that table saw blade can also cut angles, the blocks don't need to be square.
I also cut my own stringers. I dazzle the guys in the shop when I start cutting 3/16X1/8 stringers in 10 foot lengths. Not all wings use a 36 or 42 inch stringer so I cut as needed.