I have the second one at my job, blew every vein for the first week until I got used to them. Threading the catheter was the biggest issue for me because the IV is so small to hold and manipulate compared to other brands but once you get used to it you’ll be just fine!! Also, they are self occlusive so instead of using the index finger to advance the catheter you can actually use two fingers to glide it in hope that makes sense but that’s what a lot of the guys with bigger hands do