Shipping and delivery were affordable and prompt. I am running z treads on a Cat 259D, and installed 120 Grip Studs per tread in a staggered pattern (2 outside, 2 inside next tread, 2 outside, and so on). Substantial difference in drip in loose and compacted snow on my gravel drive and dirt road here in NW Montana. Where I was spinning in circles on the plowed dirt road in front of my driveway, the machine holds solid. I have once slipped off the side of my crowned gravel drive into deep snow due to operator error (white on white, hard to see at times). The Grip Studs allowed me to simply correct direction and slowly pull right back up on the drive. Highly recommended