Its only product is Spectrum, a two-stage rocket 28 metres tall and 2 metres in diameter, capable of lifting 1,000 kg to low Earth orbit and 700 kg to sun-synchronous orbit. Spectrum uses liquid oxygen and propane propellants. Both stages are powered by Aquila engines developed entirely in-house. The vehicle's primary structure is manufactured from automated single-part carbon composite, and the most complex engine components are 3D-printed from high-performance metals. Isar maintains full vertical integration from design through to launch.

Spectrum launched for the first time on 30 March 2025 from Andøya Spaceport in Norway under the mission name 'Going Full Spectrum'. The rocket lifted off successfully but was terminated approximately 30 seconds into flight after an unexpected vent valve opening caused a loss of attitude control. A second qualification flight, 'Onward and Upward', carrying five CubeSats and one experiment as part of ESA's Boost! programme, was being prepared as of early 2026. Isar operates a dedicated launch pad at Andøya and has signed a binding agreement with CNES to use the former Diamant launch site in Kourou, French Guiana.

CEO Daniel Metzler leads the company alongside CTO Josef Fleischmann and CCO Stella Guillen. The company is developing a production facility near Munich in partnership with VGP Group, designed to manufacture up to 40 Spectrum rockets annually.