…in addition to being self-stropping. According to the advertisement, that is. Just how instantly adjustable it truly was is a different matter. I do suspect less so than the copywriter claimed.

By a touch on the adjusting lug you can vary the distance between the blade and the guard with supreme precision and accuracy, according to the toughness of your beard or the tenderness of your skin.

Some poor, underpaid copywriter, 1918

From what I can tell, the “adjusting lug” they are talking about is the lever you use to release the blade for stropping. Which means that if you use it to lift the blade away from the guard, the blade is less well supported for the actual shaving.

And I might be less tough and more tender… but I do not want to shave with an unsupported blade.

As for what an instantly adjustable Valet would cost you.. .21 shilling is 1.05 pounds, also known as one Guinea (British pre-decimal currency was weird). and if we adjust for inflation, that would be 49.39£ (57.70€ / 61.89$ / 670.05 NOK) today. Not a cheap razor, but not terrible expensive either.