Lennartz has been making short- and intermediate-period seismometers since the mid eighties. If you are in the market for anything short- to intermediate period, look no further. Thousands of LE-xD instruments are in active duty day-in, day-out around the world.
LE-3Dlite MkIII: the seismometer that started it all; evolved out of LE-3D classic. Has been around since 1986 and has undergone a number of refinement cycles. MkIII (introduced in 2014) further improves on the already impressive features of MkII. Even less noise, even less power dissipation, increased sensitivity.
LE-1DV MkIII: the single-component (vertical) version of the above.
LE-3D/5s MkIII: three components, 0.2 Hz (5 s). Extremely low self noise, yet rugged and fieldworthy. The instrument of choice for H/V (Nakamura).
LE-1DV/5s: the single-component (vertical) version of the above, developed by request of GFZ (Geoforschungszentrum Potsdam).
LE-3D/BH: the downhole version of LE-3Dlite
LE-3D/BHs: the simplified version of the above, for installation in sand.