With all the talk of crebs and Bs lately, I lined up a couple other similar wire groove height adjustments. 1st: 145 CREB, 2nd; 145 B. Here's where I find it interesting: 3rd: 145 American 3 patent. 4th: 145 American 2 patent. Notice that the 3 patent has a flat top and low wire groove, both in contradiction to the patent it displays, while the 2 patent date version is a beautiful parabolic shape with the wire groove more equatorial. A great example of the patent that it does Not have embossed on it! I also found it interesting that my oldest ( I assume) Can Pac 143 (010) two piece mold, displays a "middle" height wire groove, while the rest of the EINs of Can Pacs( that I have anyways) have low wire grooves.