these powerblock work as advertise . I prefer the bowflex adjustable dumbell due to the way they adjustment mechanism work , but they be considerably more expensive and require the use of a base . these powerblock work well overal and seem to be very well construct . the magnetic pin mechanism work well , although sometimes it seem awkward insert they , especially when the insert location be near the bottom of the block . once the pin be insert , the block be very reliable and stable . I have never experience drop or partially connect weight , which be something that can occur on the similarly price weider adjustable dumbell .