X0609 4 2026-08-15 0 0000724004 MESA LABORATORIES INC /CO/ MLAB 0001305784 Sullivan John James false 12100 W. 6TH AVENUE LAKEWOOD CO 80228 1 0 0 0 0 Common Stock 2026-08-15 4 M 0 2784 0 A 20618 D Common Stock 45110 I By Trust Restricted Stock Units - 10 2026-08-15 4 M 0 2784 0 D Common Stock 2784 0 D Represents shares held by the "Sullivan Family Trust" for which the reporting person's spouse serves as trustee. The reporting person disclaims beneficial ownership of the securities held by the trust except to the extent of his pecuniary interest therein Each RSU represents a contingent right to receive one share of the Issuer's common stock Not Applicable RSUs that vested on August 15, 2026 John Sakys under Power of Attorney by John Sullivan 2026-08-17