4ft wall bracket

Anyone know if this 4ft wall bracket will actually hold a 90lb bag?

http://www.bodyhut.com/shop/prodView.asp?idproduct=1326

ive emailed them to query about the maximum weight it is capable of holding, they said 110lb. However, im still suspicious about if it will pull down my wall, the longer the arm the greater the force acting on the wall.

is this a good purchase? how long are the fixings normally supplied?

i wanted to buy a 4m beam thick enough to hold such weight but couldn't find one that long at B&Q