Store › 21" Utility Box 6" 21" Utility Box 6" $250.00 Built to fill in the gap when a 27” flag box is used. Fits the Head cart and 4X4 cart.Dimensions (LxWXH)21”X6”x24” Add To Cart Added! Built to fill in the gap when a 27” flag box is used. Fits the Head cart and 4X4 cart.Dimensions (LxWXH)21”X6”x24”