Ryobi Expand-It 18-Volt Lithium-Ion Cordless String Trimmer Power Head (Attachment Capable, Attachments, Battery and Charger NOT Included) - Walmart.com
RYOBI ONE+ 18V Brushless 15 in. Cordless Attachment Capable String Trimmer with 4.0 Ah Battery and Charger P20110 - The Home Depot