The Power 400/415 is ideal for tracking assets in harsh environments and is certified intrinsically safe (ATEX/IEC-Ex) and (C1/D1).  The Power 60/65, also an active tag is designed for tracking personnel and their interactions with tagged assets.  For tracking indoor applications, the Power 100/115 is the choice for durability and flexible mounting options with enough battery power for 4 years of duty in most applications.