Baltic Birch Plywood

Baltic birch is a premium plywood made entirely from birch veneer, both face and core, with thinner individual plies (and consequently more of them per given thickness) than standard construction-grade plywood, and manufactured to a void-free standard -- no gaps or football-shaped voids hidden inside the core, which standard plywood can have. That combination gives it a noticeably cleaner, more consistent edge when cut, strong enough and attractive enough that many jig- and shop-fixture builders, as well as furniture makers, leave the edges exposed rather than banding or hiding them.

The tradeoff is cost -- Baltic birch runs meaningfully more expensive than construction-grade plywood of the same nominal thickness, which is why it's typically reserved for work where the edge is genuinely going to show, or where the extra strength and consistency actually matter to the piece.