Selling over ten SUMTAK encoders, model IRT381-2000-519, sourced from Japan. They are in like-new condition, just disassembled from equipment. Each encoder has a different serial number: 31 459 694, 31 122 500, 31 122 501. Suitable for a +5V power supply. No issues were encountered during use; you can use them with confidence after purchase. Selling due to equipment upgrade. Interested friends can contact me for more details.