New
#11
It looks like your eSATA port was added as an afterthought by using a regular SATA port and using an optional bracket. The advantage of this is it still could be used for an internal SATA port by not using the bracket.
HP Compaq Pro 6300 Small Form Factor PC Specifications
HP Compaq Pro 6300 Small Form Factor PC Specifications | HP(R) Customer Support
HP Compaq Pro 6300 manual
User manual HP Compaq Pro 6300 (English - 104 pages)
HP eSATA Adapter
https://cdn.cnetcontent.com/40/4b/40...437cc6523d.pdf