A trill, generally three very fast notes on updating the fireball for rev 2 Battery clip for batteries with a diameter between 16-19 mm: https://www.keyelco.com/product.cfm/product_id/826 Keystone #500, CR1220 battery holder, http://www.keyelco.com/product-pdf.cfm?p=710 AA CR2 A battery holder Keystone type 105 battery holder Keystone type 104 battery holder Keystone.