The Lone Wolf Arms AlphaWolf Glock 43 9mm Threaded Barrel measures 3.98" in overall length.
The Lone Wolf Arms AlphaWolf Glock 43 9mm Threaded Barrel will work with a Glock 43X Gen 5.
This Lone Wolf Arms AlphaWolf Glock 43 9mm Threaded Barrel is for Glock 43 models and will not work with a Smith and Wesson M&P Shield 9mm. However, the Lone Wolf Arms AlphaWolf Smith & Wesson M&P Shield barrel at the link below will work for your Smith and Wesson M&P9 Shield. You will need model LONEAW-SWS9TH.
https://www.opticsplanet.com/lone-wolf-alphawolf-smith-wesson-m-p-shield-40-s-w-threaded-barrel-9-16x24.html?_iv_parent-gun-make=smith-and-wesson&_iv_parent-gun-model=smith-and-wesson-m-and-p-9-shield&_iv_gun-model=smith-and-wesson-m-and-p-9-shield&_iv_threads-per-inch=1-sl-2x28&_iv_code=59-PTB-UASG34-SWS9TH
This barrel is compatible with the 43X.
3.98 Inches
Unfortunately the manufacturer has not provided that information, even on their own site. We recommend contacting them directly, they should be able to provide you with that information. You can reach them here: https://www.lonewolfdist.com/Content.aspx?PAGE=Contact%20Us
Yes it does.
No, they are completely different platforms. You would need a Glock 19 threaded barrel, not a Glock 43 threaded barrel.
Yes fix to 43x