Stockton 5 - Key Facts Sizing – flat top 481 x 544 x 335mm (w x h x d) Sizing – high top 503 x 685 x 335mm (w x h x d) Wood burning & Multi fuel (with external riddling). High efficiency heating. Wood: 80% - Smokeless Fuel: 85%. Approved for Smoke Control Areas. Cleanburn. Airwash. Flat top & Low canopy version. Maximum heat output 4.9kW Maximum log length 330mm. No room vent required. Flue connection 128mm (5") top or rear Choice of four colours.