XBee-PRO 900HP RF Module and XBee Zigbee Mesh Kit

when creating mesh network with XBee-PRO 900HP RF Module do we need a coordinator? because nothing has been specified in getting started manual.
but in the XBee Zigbee Mesh Kit manual they mentions the necessity of coordinator.
and i would like to build a mesh sensor ad-hoc networks which of the following kit is better for me? another thing is XBee-PRO 900HP RF a zigbee dev kit?

No, the 900 HP uses a proprietary mesh which is truly Peer to peer. That is no coordinator is needed. You only need to have nodes that are in range of each other for communications to occur.

Node 1 <> Node 2 <> Node 3 <> Node 4

Node 1 is in range of node 2
Node 2 is in range of both Node 1 and 3
Node 3 is in range of both Node 2 and 4

There are many mesh modules present you can visit and check the devices you need here :