I love the SportBlock . it be just the right size to do a variety of exercise and be relatively compact due to the square shape . these dumbbell be easy to manuever and the padded grip be comfortable . in my opinion , they be also the safest design of all the adjustable dumbbell and it be very easy to change weight . the only issue with these block be that you have to be sure to insert the pin level and the pin assembly right side up . if you do not , while it be unlikely something will go wrong , it can . however , there be also a elastic safety mechanism just in case . this would not help you in a overhead triceps press , but it be a very good design and a brief safety check before you do anything over you head will give you about as good a guarantee as you would get with any dumbbell use over the head . also , these thing be rugged and the weight range be good for most people , especially if you use they along with a stability ball . a book that cover some workout that be relatively inexpensive and well do be  weight on the Ball Workbook : Step-by-Step Guide with Over 350 Photos  if you handle heavier weight than this , then you may not want to work on a ball . also , eventually if you be serious about bodybuilding or put on significant mass , you may want to upgrade to  PowerBlock Personal Dumbbell Set  many people also like  bowflex selecttech 552 dumbbell