These are very good safety item if you need to actually use that 50 lb jack thingy that we put on our off road vehicles to look cool. They greatly increase the stability of the jack. I highly recommend getting one and coincidentally, TRDparts4u has free shipping right now.
http://trdparts4u.toyotaofdallas.com/Scripts/prodView.asp?idproduct=-6211
http://trdparts4u.toyotaofdallas.com/Scripts/prodView.asp?idproduct=-6211