Bitpool

From Redump Wiki

Used primarily by games developed in Germany.

DRM is based around EDC/ECC errors but the amount of them varies greatly. Older discs will generally just have a single one but later can have as many as 110k. Like CD-Lock the DRM will commonly also have audio tracks surrounded by 2 data tracks, but unlike said DRM this is no rule and discs without it has been encountered as well.