There's a liquid type material or lubricant coming out of the massage gun in the massage head area. Is this normal?
Yes, it is normal but it will be gone after a few uses.  
Does the charger work with 220v?
Yes, the charger is rated 100v-240v
How long does it take to charge?
Around 2-3 hours to fully charge
How long does it work before the battery drains?
It works up to 12 hours of use per full charge
What is the amplitude distance of the unit?
Can I use the massager while it's charging?
No, we don't recommend using the unit while charging or plugged in
How would I know that the unit is fully charged?
All 4 LED indicator lights will give a red light (not blinking).
When the customer leaves the United States, does the customer need to purchase a transformer to use this massager?
No, our massage gun power adapters is wide voltage, if the customer is not in the United States, the customer can buy a travel adapter to use our products in other countries. Customers do not need to buy transformers.
Is it normal that the massager stops after a few second?
Yes, it’s normal. If the customer chosen a low speed level, the massage gun will change to standby mode (Or stop for a while) if the external force is too much. You can advise customers to adjust to a high speed Level while using a large external force. (I also added the video for you to check)
When I the massage gun, the massage head is ejected by itself?
There is a very high possibility that you did not insert the massage head completely. Please refer to the picture below that the massage head has been completely inserted.
Are all the attachment rubberized?