Small Single 21700 Regulated 510 Mods

Looking for some suggestions on smaller 21700 mods (510 only, no AIO or Pod systems)

I already have

– EHPro Cold Steel 100
– Vaporesso Armour Pro
– Eleaf Pico 21700
– GV Aegis Max (biggest I'm willing to go but prefer smaller like the ones above)

TC doesn't matter. Don't need it.

Edited to add: Mainstream only, around or under the $50 price range.

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