The Mitutoyo 500-196-30 digital caliper is one of the most popular precision measuring tools in the world. Known for its accuracy, durability, and build quality, it’s been the go-to choice for machinists, inspectors, and quality control professionals for decades. For years, you could find it on Amazon as a best-seller, moving thousands of units every month.
But in early 2024, something strange happened. The Mitutoyo 500-196-30 — along with many other top-selling metrology tools — simply disappeared from Amazon. It wasn’t just one brand, either. Mahr, Fowler, Starrett, Brown & Sharpe, and other big names in the precision measurement industry saw product listings vanish almost overnight.
So what happened? Why would Amazon remove products from major, reputable manufacturers? The answer lies in a tragic story and a piece of legislation called Reese’s Law.
In October 2020, 16-month-old Reese Hamsmith was home sick from daycare. At some point during the day, she managed to open the battery door on a small remote control and remove the button cell battery inside.
Her mother, Trista, didn’t realize what had happened until it was too late. Reese was rushed to the hospital, where X-rays revealed the battery lodged in her esophagus. Doctors performed surgery, but her recovery was short-lived. A few days later, her condition worsened, and she returned to the hospital. She was intubated, sedated, and remained in intensive care for 40 days.
On December 17, 2020, Reese passed away in her mother’s arms.
Before this incident, most people — myself included — underestimated the dangers of button cell batteries. We might have assumed the primary risk was choking or intestinal blockage. But in reality, these batteries can cause devastating internal burns within minutes of contact with human tissue.
To demonstrate the danger, I performed a simple test. I placed a button cell battery into a hotdog. Within minutes, the meat began to bubble. By the 45-minute mark, the area around the battery was burnt and blackened. It’s shocking how fast the damage occurs.
Following Reese’s death, her mother launched Reese’s Purpose, a campaign to raise awareness and push for stronger safety standards. In June 2021, she started a petition on Change.org that quickly gathered over 80,000 signatures. By November of that year, Senate Bill S.3278 — known as Reese’s Law — was introduced to Congress.
The bill passed with unanimous bipartisan support and was signed into law on August 16, 2022. Reese’s Law requires the U.S. Consumer Product Safety Commission (CPSC) to enforce strict safety standards for products containing button cell or coin batteries.
In late 2023, the CPSC adopted ANSI/UL 4200A-2023 as the mandatory safety standard for compliance with Reese’s Law. Enforcement began on March 19, 2024.
Under UL 4200A, any consumer product with a button or coin cell battery must meet specific requirements, including:
Secure battery compartments (often requiring tools to open)
Clear warning labels on both the product and its packaging
Documentation proving compliance through accredited testing
The key point is that these rules apply to any consumer product — regardless of whether it’s intended for children. That includes professional-grade measuring tools like digital calipers, micrometers, and height gages.
Amazon took Reese’s Law enforcement seriously. Beginning in early 2024, they started requiring sellers to submit proof of UL 4200A compliance for all applicable products.
If a manufacturer couldn’t provide documentation, Amazon would remove the listing. This enforcement hit the metrology industry hard. The Mitutoyo 500-196-30 was just one of many casualties, with other major brands losing dozens of SKUs.
The result? Customers suddenly found it harder — or in some cases impossible — to buy certain precision tools on Amazon, even though the products were still being manufactured and sold through other channels.
This isn’t just an inconvenience for buyers. It’s a major disruption for manufacturers, resellers, and the supply chain as a whole. Products that have been sold for years without issue are now stuck in limbo, unable to be listed on one of the largest e-commerce platforms in the world until compliance paperwork is complete.
For professionals who rely on these tools, this can mean delays, limited availability, and in some cases, having to settle for inferior products that are still available. For the industry, it means lost revenue and a race to bring existing product lines into compliance.
Reese’s Law was created with the best of intentions — to prevent future tragedies involving button cell batteries. But its impact has reached far beyond toys and household gadgets, into industries like ours that had never been directly affected before.
The Mitutoyo 500-196-30 will likely return to Amazon once compliance requirements are met, but in the meantime, it serves as a case study in how quickly regulations can change the landscape of an entire market.
If you’re a manufacturer, now is the time to ensure your products meet UL 4200A standards. If you’re a buyer, you may need to look beyond Amazon for certain tools until the industry catches up.
Watch the full video here: https://youtu.be/3IncAFbkL8E
In the video, I break down the whole story in detail, from the tragic events that inspired Reese’s Law to the specific ways it’s reshaping the metrology market. Whether you’re a machinist, engineer, or quality control inspector, this is something you need to be aware of.