DIN 66399 does not define one security scale, it defines several — one for each kind of material. Loose paper is category P. Hard drives with magnetic data carriers are category H, and the H scale runs H-1 to H-7 on its own terms. The two do not convert into one another. A P-7 paper shredder is certified to reduce paper to a 5 mm² particle and is certified for nothing else — it carries no H rating, and feeding a drive into it wrecks the cutting cylinders without producing a compliant result. If your destruction policy names a level, check which letter it uses before you buy anything.
This range covers H-3, H-4 and H-5. The scale as a whole runs from simply rendering a drive inoperable at the bottom end to reducing it to fine particles at the top, and the levels here differ by how far the drive is actually broken down. At H-3 the drive is destroyed as an assembly — the platters are deformed, or cut into a modest number of large pieces. That is what the Dahle PowerTEC 818 HD punch, the Kobra HDD, the intimus HDD Gladiator and the HSM StoreEx HDS 150 deliver. H-4 and H-5 require successively smaller particles: the HSM StoreEx HDS 230 reaches H-4 by cutting to 20 x 40-50 mm in a single stage, and reaches H-5 by passing every item through two cutting stages down to roughly 10 x 25-30 mm. Finer costs throughput — the same HDS 230 chassis does 360 drives an hour at H-4 and 280 at H-5.
Two quite different machines are sold under the same search term, and buyers routinely confuse them. A punch (also sold as a crusher or deformer) drives a hardened ram straight through the drive body, buckling the platters and the spindle so the disc can no longer be spun or read conventionally. The drive comes out in one piece, bent. A shredder or granulator feeds the drive through cutting rollers and reduces it to separate particles, which is what a maximum particle size is measured on. A punch is fast, quiet, cheap to own — no cutting head, no lubricant — and leaves an intact-looking object; a shredder is slower and more expensive to run but produces material that has visibly ceased to be a drive. In this range the 818 HD is the only punch — everything else cuts. Which one your policy accepts is a question worth settling before you shortlist.
Degaussing is the third method, and its limit is absolute. A degausser erases by collapsing the magnetic field that holds the data, so it only does anything to magnetic media — spinning hard drives and magnetic tape. An SSD, a USB stick, a memory card or a phone stores data in flash cells, which are not magnetic, and a degausser has no effect on them whatsoever. A punch is a poor match for flash for a related reason: there are no platters to deform and the ram can miss the chips entirely. Solid state and flash media must be cut or granulated, and those machines are in specialty shredders rather than here. Optical media is category O and is a separate scale again.
On US government work, one correction is worth stating plainly: NSA/CSS Specification 02-01 is a paper standard and does not apply to hard drives. The relevant references for magnetic media are the NSA/CSS Evaluated Products Lists for degaussers and for hard disk drive sanitization devices and deformers, read together with NSA/CSS Policy Manual 9-12. A DIN 66399 H rating is a European commercial classification, not an NSA authorisation — the two are independent, and most H-rated machines are not on any EPL. Of the machines on this page, the Dahle PowerTEC 818 HD is named on the NSA/CSS EPL for Hard Disk Drive Sanitization Devices and Deformers, under the deformers heading; note that under Policy Manual 9-12 a deformer alone is not a complete sanitisation process for classified magnetic media. EPL editions change, so verify the current list before relying on any entry. Further reading: DIN 66399 explained, the government approved range, and paper shredders for document destruction.
