Available in two sizes:
S/M (Cup entrance diameter: 22mm, 0.9"; Inner cup diameter: 34mm, 1.3")
M/L (Cup entrance diameter: 25mm, 1"; Inner cup diameter: 44mm, 1.7")
How would one know if their penis would fit in this device allowing proper function? To determine this you need to see whether the circumference of the device is greater than the largest circumference of your erect penis.
Circumference = Radius X Pi
Entrance cup circumference for the S/M: 0.9" X 3.14159 = 2.82"
Inner cup circumference for the S/M: 1.3" X 3.14159 = 4.08"
Entrance cup circumference for the M/L: 1.0" X 3.14159 = 3.14"
Inner cup circumference for the M/L: 1.7" X 3.14159 = 5.34"
It is also worth mentioning the implied usage of ALL attachment cups are based off these dimensions.
Just as a reference, the circumference dimensions of my erect penis range from 4.75" on the shaft up to 5.25" on the head. This is technically not a violation of the products dimensions however it is at the upper limit of them. The outer cup of the device is made from a highly malleable synthetic material that can expand in diameter another .5" or more with ease.
The out cup allows for a flexible range of shaft circumference while providing an air tight seal. The outer cup material and dimension is not an impediment to product usage at all, what I list below would be.
With the largest circumference of my erect penis being 5.25" at the head, it is within the 5.34" spec allowed by the M/L size device. However, upon inspection of all the available attachment cups I discovered a problem.
The malleability of the synthetic material from which all inner attachment cups are made is FAR less than the malleability of the Cyclone outer cup synthetic material (meaning the inner cups are made of a slightly "tougher" or more "rigid" synthetic material). Intuition alone suggests this would potentially cause a tremendous scaling motor drag based on circumference ratio.
Even without formal lab testing, I highly suspect the motor drag would increase exponentially with circumferences increasing from 5.00" up to 5.25" due to the lower malleability synthetic material used by any attachment cups available (with exception of the "freestyle cup" for obvious reasons).
This motor drag would occur regardless of the viscosity of ANY lubrication used for the coefficient of friction would simple become too great for the motor to overcome.
The M/L A10 Cyclone should not be used on ANY erect penis with any circumference exceeding 5.00". While M/L the inner cup circumference dimension is 5.34" it NEEDS a deal of clearance even with lube due to the lower malleability synthetics from which the attachment cups are made. This same ratio can then be applied to the S/M size inner cup.
This device is a wonderful concept but needs to come in sizes L/XL and XL/XXL with corresponding sized attachment cups based on current product scaling for the "tuna can" dudes. Or the malleability of the inner cup attachments must be increased potentially reducing the products durability.