Unlike a standard physical server or a fixed-specification VPS, a Flexible Resource pool allows you to purchase a slice of cloud resources and carve that up into as many VMs as you see fit. It allows total flexibility of the resources allocated to you!
Example
David purchases the following from DediSERVE;
4 CPU cores
8GB RAM
100GB SSD
4 IPv4 Addresses
Using this allocation of Resources David can either create one large virtual machine (Server) with the above spec, or he could instead create 4 smaller virtual machines, like below;
1 CPU core
2GB RAM
25GB SSD
1 IPv4 Address
If at any point he changed his mind, he could destroy the virtual machines, reclaim the resources and deploy differently, total flexibility!
For a closer look, check out our guide on how to create a virtual machine