The DT4221 is a digital micrometer manufactured by HIOKI. This device offers high-level safety operations in a compact and light construction. It provides ± 0.5% DC V basic accuracy and its frequency ranges from 40 Hz to 1 kHz AC V. It can handle operating temperatures ranging from -15°C up to 55°C (5°F-131°F). It works on a low-pass filter at 100Hz / 500Hz and has its current measurement function removed to maximize safety.