Motorized Wheelchair (Bismarck, Missouri 63624)

I am in need of a preferrably motorized wheel chair for a lady approximately 500 lbs. I am 69 and have difficulty pushing her in a manual one (which we borrow) when needed. If I can get her one of her own it would be great. I wouldn't have to borrow one. It would just be a blessing if it was motorized. Thank you in advance.