Angel Kiss The Original 8pcs 4 Sizes Chinese Twist Up Vacuum Cupping Cup Set;

This is the Best most simplest cupping of its kind sold on amazon by Angel Kiss, Powerful suction with this Angel Kiss cupping set of demurely sized suction cylinders. No pumps or other equipment is required. These self-contained cupping are made of medical grade plastic and are super silent and work twist. Lubed internally for smooth movement and a strong seal that makes for sublimely powerful suction.
Packing list : 8pcs - 4 different size cups
Condition: 100% brand new and high quality
Color : Clear
Inside diameter 0.7'',1.1'',1.5'',1.97''(S / M / L / XL)
Measurements:
Opening is 0.75 inches in diameter, tube is 2.35 long and entire item is 4 inches long.
For better suction use a little lotion on the suction area prior to use. The skin must be smooth and hair free for ultimate suction.
How to Use:
1-Place on the nipple
2- Hold in place with one hand while twisting the knob with the other hand clockwise
3-to Release, hold it with one hand while twisting counter clockwise with the other hand.

NOTE:If you see cupping with less oil, it is the manufacturer to better test its "TWIST", it can also have lubrication,The point is to just have some sort of moisture otherwise your rings can become brittle and crack making it loose suction ability.
If not lubricated, Best to use something called "petroleum jelly" or even "baby oil". Twist them all the way out so the inside cylinder comes out than use the mentioned lubricant to lubricated specially the black "O" rings and than place them back in and twist them up and this should solve the issue for long time.
Please don't worry