Sorry for the confusion (I was probably sorting out your use of devices/devises; both of which are correct, depending on your choice of English). 

I meant to use "devices' characteristics" for a group of devices, or in the case of a specific device, then "device's characteristics." 

A simple workaround is to use "the characteristics of these devices" or "the characteristics of this device.â€

If this is still unclear, let me know and I’ll review the text and amend it accordingly. Thank you, as always.