The majority of today's small arms smokeless powders are made of either a nitrocellulose base, referred to as single base powders, and typified by the IMR powders, or of a nitrocellulose and nitroglycerine mix (usually from 3 to 39 percent), called double base powders, which include powders like Bullseye, 2400, and Hi-Vel #2. An early form of smokeless powder was Cordite, which was a double based propellant made of 65% nitroglycerine, by weight, 30% guncotton and 5% petroleum jelly, and loaded as spaghetti-like strings of powder. There are also some special double base ball powders available in non-canister powders. Double base powders have a higher energy potential than single base powders. Some modern powders referred to as "triple base" now incorporate an additional ingredient like nitroguanidine, but these, like the double based ball powders are not in wide distribution except military powders and some commercial grade non-canister powders. They can yield a substantial increase in velocities while maintaining normal peak pressures as they give a longer, flatter pressure curve. In addition some manufactures are using "blended powders" for some of their high performance ammunition.