I use a brand of strippers/crimps/heatshrink tubing called Wirefy that I found on Amazon. Far superior to any normal butt connector or heat shrink butt connector. the heat shrink tubing is 3:1 with adhesive inside. I highly recommend. I also use the yellow handled Klein strippers that Fingers77 shared










https://www.amazon.com/gp/product/B07Q32PYP3/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B08BYXP4RF/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B084GDLSCK/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1