Within the NG-SHM servo-hydraulic family, the A, B, C, D, and DP versions mainly separate by frame architecture and how the test space is laid out. The biggest divider is dual-zone frames, which let you keep a compression setup on the lower platen while running tensile tests in the upper zone, versus single-zone frames, which create one large, uninterrupted space for tension, compression, and fixture-based tests when specimen length and access are the priority.

Series A is the dual-zone, multi-column configuration used when you want fast changeover between routine tensile and compression work without repeatedly tearing down fixtures. It is a strong fit for high-force metallic QA/QC, batch release testing, and labs that run the same methods every day across rebar, plate, bar, tube, and fasteners.

Series B and C are also dual-zone, 6-column frame styles, typically selected when you want that same dual-zone workflow but with a frame layout matched to specific specimen handling needs. Class C is commonly chosen when the gripping area and jaw geometry need to better suit stranded steel wire tensile testing.

Series D and DP use a single-zone frame with the actuator above the test space. This layout is typically preferred for extra-long specimens, high-elongation materials, and setups where you want one open working area for tension, compression, bending, and similar fixture-based tests. DP is a variant that pairs the single-zone concept with a side-action wedge grip approach for tensile work, which can be helpful when access, ergonomics, or gripping workflow drives the decision.

If you want to confirm the best class for your specimen geometry, elongation, and day-to-day changeover needs, use learn more and then request a quote with your material, specimen type, and the grips or fixtures you plan to use.