Question 1: What does 6.5 mean? And what's the weight limit and what is the age for this product?
Answer: The 6.5 means the tires is 6.5 inches. The MAXIMUM weight limit is 180 lbs. There is no age limit on this hoverboard if that's what you're asking. 
Question 2: Does this product have warranty? And how long?
Answer: Yes, we provide 1 year warranty for this hoverboard.
Question 3: How long does it take to charge?
Answer:  It takes 3 to 4 hours to be fully charged. 
Question 4: Does it come with a carrying bag?
Answer: No, the carrying bag is not included.
Question 5: Does it come with a charger?
Answer: Yes, the charger is included.
Question 6: Dose it have a hove cap?
Answer: No.
Question 7: Can it be used on dirt or grass?
Answer: Yes, but it will cause the board to move slowly. 
Question 8: My board is stuck in forward, does anyone know how to fix this
Answer:  We would suggest you calibrate the hoverboard to have a try, please lay it down on a flat surface, and then press the power button about 15 seconds.

This hoverboard support Bluetooth function, you could just use it to listen music.

HIGH LIGHTS:
HIGH QUALITY- Two Hours Charging, 12km/h Top Speed, 12.5 Miles Range and Weight Up to 220 lbs.
RIDE SAFE- UL 2272 Certified Smart Battery! No potential fire hazards.
MORE POWERFUL-Our hoverboard has Dual 300W Motors that help it climb slopes as steep as 25 degrees, making it the more powerful balance board on the market.
UPDATED FEATURES- LED headlights, battery indicators, rubber bumpers and two riding modes（Beginner and Advanced).
GET FASTER - One Day Processing, 2-5 Working Days Fedex Ground Service Shipping!
WARRANTY- One year limited warranty.
UL Certified US Standard Wall Charger, Double Protection, Double Safety!

SPECIFICATION:
UL 2272 Certified: Yes
Category: Two-wheel Self-balancing Electric Scooter
Battery: 36V 2000mah UL certified lithium batteries(Safe for ride)
Tyre Size: 6.5"
Body material: ABS + PC
Moter power: 300W x 2
Maximum speed: 12km/h (depends on rider's weight, road conditions etc)
Running distance : Approx 10-15KM (About 12.5 Miles, depends on load and terrain)
Climbing capacity: approx 25°(depends on load)
Low battery protection: When battery is lower than 10%, it will slow down and finally stopped working
Working temperature: -15℃-45℃
Charging Temperature: 0℃-40℃
Charging Voltage: AC 110-240V 50-60HZ
Charging time: Approx 4hours
Net Weight: 8.66KG/19Lb
Maximum loads: 180Lbs
Body size: 635x 240 x 235mm
Waterproofness: Daily life waterproof

WHAT IS INCLUDED:
1x Self-balancing Scooter
1x US Plug Charger
1x English Manual