One of the faster 4TB drives, perfect for DVR recording. At risk of extremely long delivery times due to the current logistics situation and standard warranty issues that comes with overseas import.
The 7200rpm means it'll be louder than standard reds/iron wolfs. HGST has a good drive readability track record if you look at Backblaze's drive data.
The limit is 1 drive sadly.
edit:reports of it being renewed/already used drives both from last ozbargain post https://www.ozbargain.com.au/node/536194.
The product page says that the items are 'renewed'. Sounds like they are refurbished, given that HGST products have not been sold with the brand since 2018? https://en.wikipedia.org/wiki/HGST