Oh sorry its supposed to be 15 months :)
You can use any but make sure the teat is as close to a natural nipple or it can interfere with his/her latching onto you. A bottle is less work then breastfeedibg for the little one to get the milk.
I breastfed my son till 25 months still doing night feeds atm but wanting to fully stop.
I only pumped once when i had to have an operation so he could stay at my sisters.
Its hard at first but so enjoyable :)