Router
https://www.amazon.com/gp/product/B07WDR7N3R/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
Bits
- router bit-groove for drywall under stairs. Allows closing wood gap in drywall. Major pain as it would require predrill. [1]
https://www.amazon.com/gp/product/B07WDR7N3R/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1