An after-market Blu-ray Disc writer that can be added to existing desktop PCs will be sold by Sony as of next month.

The BWU-100A drive supports burning to single and dual-layer BD-R (single-use) or BD-RE (rewriteable) discs. A single-layer disc can store up to 25GB of data or about two hours of HD (high-definition) video, while the dual-layer disc can accommodate twice these amounts.

The drive will be bundled with CyberLink's BD Solution burning software. The drive can write at 2x Blu-ray Disc speed, so burning a full 25GB disc takes about 50 minutes, Sony said.

Additionally the drive can burn single layer 4.7GB DVD+/-R/+/-RW/-RAM discs, 8.5GB DVD+R double-/dual-layer discs, and CDs.

The drive has an ATAPI interface and fits into the standard half-height drive bay that exists in most desktop PCs. Sony recommends minimum computing power of a Pentium III 800MHz or faster processor for data burning. For real-time video authoring and editing, a Pentium 4 1.6GHz or faster is recommended.

Sony cautions that additional software and hardware is required for playback of commercial movies on Blu-ray Disc (BD-ROM) but the company didn't specify exactly what is required.

The drive will cost $750 (about £410) in the US. Sony has not announced pricing or availability for other markets.