L.L. Bean is recalling children's insulated water bottles because of concerns about lead contamination.

The Consumer Product Safety Commission says the bottles were imported by GSI Outdoors and sold by L.L. Bean from July 2015 through May 2016 for about $20. The 13.5-ounce bottles have five prints: sharks, dinosaur bones, camouflage, flowers and butterflies.

The Maine-based retailer said it specified the bottles should be lead-free, but routine testing by the Chinese manufacturer revealed lead solder had been used to seal the bottoms of some of the bottles.

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Ingesting lead is harmful, especially for children, who can suffer developmental delays and other health problems if high levels of lead build up in the body.

The affected products have an item identification number 297684 printed on a sticker on the bottom of the bottle. Also printed on the sticker are "PO#844" and "BB2D2-LLB-R45-0413."

"All of us at L.L. Bean are firmly committed to providing our customers with the best products and service," the company said in a statement. "We regret any inconvenience this has caused; however, your child's safety is most important to us."

A spokeswoman says L.L. Bean is instituting a voluntary recall. Consumers should stop using the water bottles and contact L.L. Bean to return the product and receive a refund.