Maker: Sheaffer. You may be looking for a different model of Admiral, depending on vintage; there is a military-clip Balance, the Touchdown in fat and Thin Model, or the Snorkel version to consider. This page refers to the Triumph era version.
Prior to the introduction of the Triumph line, “Valiant” was applied to an upper-end Balance pen with a military clip. If I have understood the available material correctly, this use of the name persisted with the model gaining a Triumph point when they became available in the following year, and that the title was retained after the dropping of military clips altogether in 1945. After 1945, the Valiant certainly appears as a broad-banded expression of the line, as high in cost as a plastic-capped model could rise without the application of a solid gold band. Initially called the Valiant II, the band was very broad indeed, very nearly as wide as that on the ur-model Triumph; this settled down by 1947 to a size that would persist, as many of the trims of this era, right through the 1960s. The settling down was accompanied by a shedding of the Roman numeral in the name.
Production Run: 1945 – 1948.
Cost When New: $12.50 (for modern value, try this calculator).
Size: 13.2 cm long capped, 15.1 cm posted, 11.2 cm uncapped.
Point: 14k gold triumph with platinum mask.
Body: Celluloid until 1947, then Forticel.
Filler: Vacuum, capacity approx. 1.2 ml or lever, capacity approx. 0.9 ml.
Sheaffer Valiant II, black vacuum-filler. In 1945, the band was extremely wide, although still down from the vast thing that introduced the line.
After 1946, the band settled down a little to mere bigness. Googling has produced no insight into the identity of the previous owner.
If you are relying on the preceding information to win a bet or impress a teacher, you should read the site’s scholarly caveat. Remember, this is the internet, and it’s full of bad information.