EKG ruler with seconds scale for PR, QRS, cycle, length, coupling, escape, and parasystolic intervals. Measures just 1 3/4" x 6 1/2". Includes protective sleeve.
My first order apparently got lost in the mail. Waited over 3 weeks and items never arrived. However, I called customer service to complain and they said they would send another order to me. I didn't expect them to overnight it, but they did. I received my order today. Customer service rocks!! Thank you.