KujectDirect via Amazon has Kuject Heat Shrink Solder Seal Wire Connectors Kit 120PCS for $5.99 when you use code *H6WWYMWQ *at checkout
https://www.amazon.com/dp/B073RMRCC3?
Brief · Source report
120-Ct Kuject Heat Shrink Solder Seal Wire Connectors Kit $6
