well i put doubles on today, and well, all i have to say is WOW! i couldnt belive how much they help, i wish i would have done this sooner. they cut up sooo fine and crisp, im not sure, but i bet it allows more grass to be put in the bag too because of its small size. i just figured i would tell ya, i was sceptical about it before, but really glad i did! only thing is, i wont be using it this week, im demoing a gravely 144z tommarow gonna see how i like it and maybe buy a 144z or a 34z, im leaning towards the 34z sense i have a 48, but idk, if i can sell the 48 soon, then i'd get the 144z.