We love our NEW Poly Farm Stackable Carboys. The 70mm neck is smooth faced for an easier seal with the gasketed cap. Easier closure means convenience and less dependency on cap wrenches. Our Samson compatible 70mm cap wrenches (available separately) will still work on these Poly Farm stackable carboys for those of us who just don't have the grip that we used to. The 70mm caps are equipped with a tamper evidencing locking ring that will break free when opened after initial use. Cap is reusable without the tamper evidencing ring. Easily removes if that function in not wanted. The center of the cap is threaded (3/4 NPT) with a knock-out membrane for use with a spigot (available separately). The separate rear vent is larger, pre-drilled, foil sealed, has vertical orientation, and has a larger gasketed cap. Stacking is positive and reversible (heal to toe or toe to toe). Approximate dimensions are 9.75" x 11" on the footprint and approximately 14 1/8" tall overall. Expect modest swelling when filled. 70mm neck is equipped with a dust plug that can be discarded when ready to use. Always use best practices when preparing containers and materials for storage. Refer to the FEMA website for US government recommendations for water storage. Shipping within the 48 contiguous states is included in the price. Hawaii, Alaska, and protectorates may incur additional shipping fees.