The Crystal Jellies Delight by Doc Johnson are a pair of jelly butt plug of two different sizes in the same package. For my wife and I this was an excellent purchase since it came with a smaller plug for me, since I'm still a beginner to anal play, and a larger plug for her.
For me the smaller plug was just the right size for giving a nice feeling of fullness and a firm, but giving surface to squeeze during climax. The progressively larger bumps we a nice sensation as it was being inserted.

Even taking into account the material safety factor these are determinately going into the toy rotation.

The Crystal Jellies Delight are made from Sil-a-Gel. Unfortunately the sil-a-gel material only rates a 5 on the Eden safety scale. The material is slightly squishable, but still plenty firm for the job and becomes nicely slick with water or silicone-based lubricants. Unfortunately it's hard to completely sanitize so the toys really shouldn't be shared.

Here is a link to the info from the Eden Safety page. https://www.edenfantasys.com/info/sexuality-articles/sil-a-gel

The Crystal Jelly Delights have a fairly standard butt plug design, but (butt) they execute it well. The bumps have a great valley between them so that you feel each one as it's inserted with how they get progressively larger; you get a great stretching sensation without increasing too quickly.
The base has an excellent flare so you don't have to worry about the toy being 'lost' without being so wide that it's uncomfortable between the cheeks either during sex or just walking around.

These jelly butt plugs performed exactly as you would expect and maybe a bit better. With the exception of the material they are made of I can't really come up with anything I'd change.

For me the smaller size was just the right size for a full feeling without being too larger or small. The jelly material they are made out of slides great when it's lubricated, plus is soft enough for a great squeezing sensation during climax while being firm enough to make insertion easy.

It might have been better if it was a bit longer and curved for p-spot massage, but that isn't what it was sold as. These were designed and sold as simple butt plugs and they perform their job well.

Care and maintenance of these is both easy and difficult. Because of the sil-a-gel material they aren't as easy to sanitize as toys made out of silicone. For me and my wife, we each just claimed one of the toys for our own and make sure to wash them well with soap & water plus a cleaner wipe both before and after uses.