Singer ProSeries Thread Conditioner Wax. 

5 mini beeswax with individual holders. 

These spools of beeswax are designed as an accessory to thread, strengthening thread as you sew to reduce breakage and stabilizing it to prevent tangling. 

Just align your thread over the slot in the spool and coat by pulling the thread through. 

Great for general use or thread you can't risk breaking.    

CHK-54301DS