PART#:  DTM-A1+TM-506
 
1、This is a TOWA Tensiometer with a PFAFF BC-PF  type bobbin case insert holder.
 
2、Compact design with easy-to-read LED display provides 12-times the measuring rage of prior Towa units
 
3、Measures tension of both bobbin case thread and upper thread with one compact unit
 
4、Battery operated (3 AAA battery, not included)
 
You can use this gauge to preset the tension on each bobbin case.   To make sure every bobbin case change is the same and eliminate the need to run a pre-test on your sewing project for loose, or tight stitching.
 
Instructions included in box.