A righting swivel is intended to orientate the anchor correctly for the bow-roller, and may be of some assistance if a regular swivel is still giving problems. They present all the pros and cons of any swivel, and tend to suffer from the disadvantage that they are physically longer and so may not easily fit between an anchor and windlass.
They do however in general work very well, rotating the anchor in a controlled and non-violent fashion and ensuring a smooth recovery onto the roller.
Below follows a series of photographs illustrating a righting swivel dealing with an anchor which is upside-down. This anchor is over-sized for the boat, and the roller is small and not well suited to handling 'serious' anchor gear. Note how the anchor is completely rotated before it comes onto the roller, and note also how the chain ends up straight without twists.