"Slender" and "gradual" are two words that describe the Spectra perfectly. Unlike many of the toys I've reviewed, I found this toy to be great for those who want to train their bottoms for bigger exploits.

The tip of the Spectra is 3" in circumference, made completely of jelly, and is entirely flexible so it may take some maneuvering to get it in at first. While that may seem to be a negative feature; I found it quite useful during back door spelunking. The flexible tip allows it to self-navigate through your nether regions and so helps avoid the infamous gut stabbing of anal adventures.

That first third is a baby step, the middle bulge is where the fun begins. The toy increases to a circumference of 5" over a good smooth length of jelly. Its stealthy growth feels fantastic and really helps you train for bigger sizes by its gentle, gradual increase instead of coming to an abrupt "stop or get over it" wall/flare such as the Severing style anal plugs. The removable vibrator spine also begins here at the center bulge, as do the the amazing vibrating sensations. The depth and circumference that the Spectra reaches upon the second bulge is perfect for the next tier of medium sized toys or for sexual intercourse.
The third bulge reaches the maximum girth and depth of the Spectra statistics at 6" circumference and 8" deep. This will take some practice to achieve as it reaches the 6" circumference barrier.

Made of 100% jelly without any mold/casting seams! The uniform smoothness is excellent for those learning to take it deeper. It is highly pliable and gives easily. As with all toys, it did have a new toy smell to begin with, but it quickly dissipated after a good cleaning and some use. The inner vibrator is standard plastic with a ridged twist cap for grip.

This is one of the few toys that can be categorized under "Transitional Toys", as it helps break the 3"-5" or 5"-6" barrier. I find jelly to be the excellent medium for anal use, (in regards to sizing and comfort) as it is very forgiving and spongy/squishy for a tight posterior.
The vibrator core can also be removed before use for an overall size decrease. So it's like having a small and vibrating medium sized Spectra for the price of one! Brilliant!

The inner vibrator of Spectra is standard. Twist for on or off, and twist off completely to access the battery compartment. Spectra uses 1 AA battery.

While the jelly part of the Spectra is completely submersible, it is inadvisable to use it in water with the vibrator included. The vibrator lacks the important rubber O-ring that seals water out of the battery casing. It won't be fatal for you to try, but it might be for the vibrator.

While I always advocate for anal jelly toys, they are not the safest things to share in regards to bacteria. Using toy covers is always advisable when sharing toys or switching from anal to vaginal. Wash before and after use with a mild soap and warm water. Store in a cool, dark place.

Water and Silicone lubes are safe to use with jelly.