Hi Michaela, I posted this recently somewhere else. Maybe useful here
I have copied links below from amazon of what I use. I added the insert because it is softer and more comfortable. You may need to trim it. The pump comes with a squeezy ball type pump which soon becames ineficient so I got the scissor grip one. The pump also comes with a ring which is rubbish, so you will need to get others if you want.
I dont know how to make the links work properly so you will need to copy them to your browser.
https://www.amazon.co.uk/Pipedream-Pump-Worx-Potent-Black/dp/B005EILA1G/ref=gp_aw_ybh_a_1?_encoding=UTF8&psc=1&refRID=4X5D34XDQ8142FY27WMT
https://www.amazon.co.uk/You2Toys-Transparent-Replacement-Cuff-Pumps/dp/B004D755GU/ref=pd_aw_fbt_img_2/257-6491659-0966014?_encoding=UTF8&pd_rd_i=B004D755GU&pd_rd_r=0c552ce1-25f3-11e9-bc3f-c119fe0d879a&pd_rd_w=cBAC7&pd_rd_wg=HqZDk&pf_rd_p=829773a1-0532-4117-a22f-5a653a869422&pf_rd_r=EYNNR36078DTPBS0Q8WA&psc=1&refRID=EYNNR36078DTPBS0Q8WA
https://www.amazon.co.uk/gp/aw/d/B001LYZ5RC/ref=ppx_yo_mob_b_post_ship_o0_img?ie=UTF8&psc=1
Good luck
Cheers
Bill