the Power Block Classic 45 be a must have if you be do the p90x Extreme Home Workout . yes like with anything man make you will need to be careful but all the safety information be cover in the handout that come with the block , I be amaze at people complain about the pin and if it be not perfect this and that could happen , all be cover in the handout that come with the block , I be use a pair of end screw on dumb bell and you talk about a pain . pause the dvd , unscrew the end , and remove the weight , screw back on the end , un-pause the dvd . so after that routine the power block be a gift from heaven , I work out on carpet and find it easy to roll the block on they side to change the weight , the pin go right in and it give I a moment to do a little check , and I do this without pause the dvd . the power block appear to be a little pricey , especially if you be on a budget . it be mainly because you be pay for all the weight upfront , unlike with dumb bell where you buy a set and when you need more resistance you go out and buy other set , and keep repeat this process until you have spend double of what the power block cost , the main thing here be it be not all at one time , the buying be do over month even year . I really can not tell you how much I enjoy do p90x now with my power block . and in the end if you be look at the power block you have make a decision to get in shape and you can not put a price on you health . only a doctor can do that and trust I it get expensive .