The Tantus O2 Revolution is the only one of the first-generation O2 models still in production, and a quick look at its design features helps to show why. It's a large, real-feel dildo that leverages the design of the Tantus Goliath, but executed in Tantus' dual-density O2 material to mix a soft, cushy exterior with a stiff inner core. Tantus has also used the dual layers to good visual effect as well, as the O2 Revolution has a translucent soft coating over either a blue, pink or purple center to give it a soft coloration that changes with the lighting. The effect allows the O2 Revolution to be a realistically styled dildo that still manages to not look hyperrealistic.

The O2 Revolution has an unusual reverse-taper along the shaft. While many dildos have a wider head that then narrows into the shaft, the Revolution's narrowest part is near the base, with the shaft gradually tapering out as you go closer to the head. The head is quite abrupt, and the Revolution reaches it's maximum size a mere 3/4 of an inch from the tip. The result is almost club-looking, but the bulge at the top is positioned well for G-spot or prostate stimulation. The head is made entirely out of the softer O2 material, providing a very comfortable and squishy tip to rub against your G-spot or prostate. Note that the rapid expansion of the Revolution makes it a toy for more advanced anal players, since there's very little warm-up time. A curved shaft would enhance the stimulation even more, but the Revolution does OK without it.

The base of the Revolution betrays this as an older Tantus product. In common with many of Tantus' older toys the base is small, with less than half an inch of flare coming out. The base is made from the stiffer silicone, so it's easy to hold and safe for anal play, but it's not big enough to reliably set the dildo down on standing upright. The small base flare also makes it important to have a close-fitting O-ring if you're planning on using the Revolution in a harness, as a loose O-ring can allow the toy to pop out of the harness during play.

The Revolution is heavily textured with wavy vein-like ridges covering the shaft. Since the texture is in the soft surface silicone it doesn't irritate or overwhelm under ordinary circumstances. The texturing also helps to hold lubricant during use. The combination of pronounced texturing and soft, sanitizable material makes this a good choice if you're looking for a crossover dildo that can be used anally or vaginally - provided you can comfortably take the Revolution's size.

As the O2 Revolution is 100% silicone, use and care are easy. Wash after use, sanitize when needed with bleach or boiling water. Since the surface layer is much softer than ordinary silicone you do need to take more care to keep it from being cut or nicked, and it's a good idea to be even more careful with silicone lubes than you would otherwise. With basic care the Revolution is a lifetime toy that will stick with you for a long time.