Released in 2007, the Sigma B-flat is available in a gold, silver and brushed matte lacquer finish. Specifications include a .462-inch bore, medium, high precision metal valves, and a concave lead pipe made of nickel-silver. It also has a top spring valve, nylon valve guides, a tuning third valve slide, and a first valve thumb hook. It has two water keys, and weighs 2.4 lbs.
Released in 2001, the Concept TT features a reverse "twin tube" lead pipe and a nickel-silver outer tube. It is available in gold, silver and brushed metal lacquer finishes. This instrument has a .462-inch bore with a tapered bell that measures 5.08 inches in diameter. Its inner pipe is constructed of brass. The valves are Monel with standard and heavy bottom valve caps. This instrument type has a third slide tuning ring and weighs just over 2.75 lbs.
Released in 1995, these models were manufactured with a gold lacquer, brushed lacquer, silver plate and with an upturned bell. All have a .462-inch bore with a medium bell size of 5 inches in diameter, high precision metal valves with top springs and nylon valve guides. They have two water keys, and weigh 2.3 lbs. They include a B-flat silver-plated mouthpiece.
Released in 1977, these models had a .459-inch medium large bore, a red brass lead pipe and nickel-plated silver valves. The bell of this series is a two piece yellow brass that measures 4.75 inches in diameter. It also featured two water keys, a first slide thumb hook, and an adjustable third slide finger ring. All were made with a clear lacquer finish with brass inner and outer slides.