By default, each Datacenter IP address supports one device at a time. If you need to use a single IP across multiple devices simultaneously, you can get a "Multi-device access" add-on when creating an order.
Currently, multi-device access is available in the following configurations: 3, 5, or 10 additional IPs per proxy. Each additional IP is priced at 50% of your order fee.
There are no limits on the number of threads per device, but all proxies are subject to Fair Use.