help with wings script

i want to add wings addon to the shop but i dont know whats worng with this code :


ITEM.Price = 15000
ITEM.Model = 'models/wings/wings_folded.mdl'
ITEM.Bone = 'ValveBiped.Bip01_Spine2'


function ITEM:OnEquip(ply, modifications)
ply:PS_AddClientsideModel(self.ID)

end

function ITEM:OnHolster(ply)
ply:PS_RemoveClientsideModel(self.ID)

end

function ITEM:ModifyClientsideModel(ply, model, pos, ang)
model:SetModelScale(0.7, 0)

pos = pos + (ang:Forward() * -29) + (ang:Right() * -2) + (ang:Up() * 0)
ang:RotateAroundAxis(ang:Right(), 270)
ang:RotateAroundAxis(ang:Forward(), 0)
ang:RotateAroundAxis(ang:Up(), 90)

return model, pos, ang

end

the wings dosent show in the shop any idies ?