Guaranteed to fit Rockwell SoniCrafter oscillating multi tool models:

Rockwell RK5100K SoniCrafter
Rockwell RK5101K SoniCrafter
Rockwell RK5102K SoniCrafter
Rockwell RK5105K SoniCrafter
Rockwell RK5106K SoniCrafter
Rockwell RK5107K SoniCrafter
Rockwell RK5108K SoniCrafter
Rockwell RK5110K SoniCrafter
Rockwell RK5111K SoniCrafter
Rockwell RK5112K SoniCrafter
Rockwell RK2514K2 12V Lithium Tech SoniCrafter
Rockwell RD5511K SoniCrafter

Compatible with:

AEG Multitools (older models), Challenge Xtreme, Draper, Rockwell Sonicrafter Old Original, Worx Sonicrafter Old Original, Parkside PMFW 280 A1, Ridgid JobMax (older models), Ryobi JobPlus (older models), Shop Series RC5100K Sonic Tool, Smart Multitool, Task Force