Narrow mouth and wide mouth bottles, available in natural and amber, are for use in the analyses of metals. I-CHEM Certifiedâ„¢ 300 series bottles include a Certificate of Analysis that lists detection limits for specified analyses. Manually readable bar-code labels are attached to each bottle with production number for complete traceability. High-density polyethylene bottles have polypropylene caps attached and are guaranteed leakproof for safe sampling, shipping, and storage. Bottles are precleaned. Sample-analysis labels are included, unattached.