I believe this is what you want if you bought LMR400 cables
wlaniot IPX/u.fl to N Type Female Pigtail Cable (6" RG178 for PCI WiFi Card Wireless Router Gateway External Antenna etc. https://www.amazon.com/dp/B08ZYK5SL9/ref=cm_sw_r_apan_glt_fabc_RC1CEVFK4QW2P876RX05?psc=1
This is the one I like, its an Ipex N type bulk head. meaning its meant to poke through the box and mount the cable out side. you will beed an LMR400 with two N type male connections.
Pig tail
https://www.amazon.com/gp/product/B08ZYK5SL9/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Cable