What size of the clip in extensions should I use for short hair? By Hair Extension AngelsOctober 25, 20160 Back to Home If your hair is just a bit longer then a Bob hairstyle, please do not go for 24" or 22" inch clip in extensions. Unless, you don't mind to take the time putting them in properly. It will take a longer time to blend them In with your own hair and you will have to get them layered at the back, so they do look natural. For a quick wear go for 12" to 14" inches maximum to give your hair volume and natural appearance. Back to Home