Getting following error while running systemd timer

Question

    [Unit]
    Description=Timer to stop ir_agent service

    [Timer]
    OnCalendar=*-*-* 04:23:00
    ExecStop=/bin/sh -c 'systemctl stop ir_agent.service'
    Unit=ir_agent.service

    [Install]
    WantedBy=timers.target

Error: /etc/systemd/system/ir_agent_stop.timer:6: Unknown lvalue 'ExecStop' in section 'Timer'

I couldn't fine the error in the unit file can someone help me.