What to look for in a percussive massage gun?

Speed and power: 

These two elements are definitely the most important. Everyone's pain tolerance and massage preferences differ, but anyone can benefit from a massager with at least two settings: one being less intense so you can still use the gun on very sore muscles where you are experiencing muscle tension or pain.

SUNGPO Massage Gun with powerful 24V brushless motor,reached to high stall force over 15kg. 

Type of motion: As discussed in the Nordictrack description, percussion and vibration are very different. When shopping for a massage gun, consider which mechanism is more important to you. 

Portability: If you're going to be traveling with your massage gun, you'll want one that can easily fit into a bag or suitcase, or one that has its own carrying case. Though most are indeed handheld massagers, some units are rather bulky, such as the SUNGPO models.

Attachments and accessories: Where on your body will you use the massage gun? If you'll only use it on just your large muscles, such as your back and legs, you probably don't need many attachments or accessories. But if you intend to use it on specific areas and trigger points, such as the arch of your foot or your neck, you'd benefit from smaller attachments intended for those specific areas. SUNGPO massage guns offering 17 different massage heads.

Battery life: Pretty self-explanatory -- the longer the battery life, the better, as with all electronics. SUNGPO provide with different choices for 1500mAh / 2000mAh / 2500mAh / 2600mAh which suitable to different usage.

Cost: Of course, you'll want to look for a therapeutic massager device within your budget. The most expensive massage guns usually offer more adjustable speed, power and motion settings, but less expensive models can certainly get the job done. 

Working in silence: Thats really the most important who will concern when using a massage gun in high stall force.Its really annoying when use some massage guns. SUNGPO massage gun solved the problem and working quiet below 55dB even at the largest speed 20.