These are simple in design. The tubes that keep the cuffs in place are made of a soft squishy PVC with black PVC caps. They feature plastic buckles for adjustment of the length of the straps, and fasten with Velcro. The cuffs are made from a synthetic velvet and are quite comfortable. They're fairly adjustable and should fit small to somewhat above medium sized people. The strap is nylon and attaches to the tube with a loop. It's fairly sturdy, and should last a good long time.
The Velcro closure means they come on and off quite easily and the velvet material is comfortable, but a cloth bondage cuff is rarely a serious bondage cuff. These are not padded cuffs and will dig into wrists/ankles if you strain heavily against them.
These are fairly comfortable and reasonably sturdy, but the ability to slide one's hands together combined with the Velcro closure makes these exceedingly easy to escape. Other than that though, provided I didn't strain against them too much, they were comfortable, did not chafe and did not come loose from simple yanking.
For a cheap basic bondage cuff these are very very serviceable. Despite their less than beautiful appearance and lack of versatility (these pretty much only work for door jams) these are a very good set of bondage cuff for bondage beginners.
As stated the Velcro closure makes them easy to put on and take off, and if not put under excessive strain they should last you a good long time.