REMEMBER ACCURATE MEASUREMENTS ARE IMPORTANT. Please read this guide carefully before placing your order, as cylinders can not be changed or returned due to health concerns. Expansion cylinders are available in several different sizes to meet your individual requirements. All measurements must be made at the widest part when you are 100% erected.  

Pleasenote: All measuring alternatives provided here are approximate.  www.bostonpump.com will not guarantee the accuracy of these alternatives and you will beresponsible for your final size and the size of your cylinder.

ALTERNATIVE 1:

Take a ruler and measure ACROSS your penis at the thickest part when erected. Add a 1/4"-1/2" to your measurement if you only wish to pump your penis and 1/2"-1" if you wish to pump your penis and scrotum simultaneously ...and that will be the size of the cylinder you need to order...(fig.1)

(fig.1)

ALTERNATIVE 2:

Simply use a soft plastic ruler, wrap the ruler around your cock at the widest part when erected. The widest area is different for everyone. It may be at the base or at the head or any where in between. Based on your reading use the following chart:...(fig.2) 

Measurement per Cylinder Size

4 3/4" ------ 1 1/2"

5" ------ 1 3/4"

5 1/4" ------ 2"

5 1/2" ------ 2 1/4"

5 3/4" ------ 2 1/2"

6"------ 2 3/4"

6 1/4" ------ 3"

6 1/2" ------ 3 1/4"

6 3/4" ------ 3 1/2"

7" ------ 3 3/4"

(fig.2)

ALTERNATIVE 3:

Measure the inside diameter (across) your favorite cockring

If you are only enlarging your cock , you will need a cylinder 1/4" larger than your cock ring. A good guide is that an average cock requires a 2" cylinder.

If you are enlarging both your cock and your balls, you will need a cylinder 1" larger than your cock ring . A good guide is that an average cock requires a 3" cylinder. Also for those who like to pump their cock + balls enormously we definitely recommend using the 2 stage cylinder

TO ASSURE THE ACCURACY:

• Always take more than one measurement and take the average of the all readings
• Use and compare at least two of the above alternatives (specially NO. 1 and NO. 2) and make sure all of them falling in the same range
• Size yourself during different times of the day
• make sure the thickest part always is at the same place of your penis

NO EXCHANGES OR REFUND WILL BE GIVEN FOR ORDERS WITH WRONG SIZE CYLINDER