Earlier this year, Apple (NASDAQ:AAPL) launched its new iPhone 5s but was plagued by supply constraints. In an effort to gauge availability, Piper Jaffray analyst Gene Munster polls 60 Apple Stores within the U.S. to check inventory. These polls have shown a significant improvement in recent weeks, hinting that Apple is now catching up with demand.

In early October, just 8% of stores polled were showing full iPhone availability. Two weeks ago, this figure was at 24%. Now, a healthy 100% of stores polled have plenty of iPhone 5s units to go around, a remarkable improvement in just a matter of weeks. That's good news as a proxy for Apple's overall supply situation and production rates, even though most iPhones are now sold abroad. The product mix will likely shift even more toward international sales in the coming quarters with the recent addition of NTT DoCoMo as a carrier partner and the expected launch of the iPhone on China Mobile later this month.

In this segment of Tech Teardown, Erin Kennedy discusses Apple's iPhone 5s with Evan Niu, CFA, our tech and telecom bureau chief.

Erin Kennedy and Evan Niu, CFA, own shares of Apple. The Motley Fool recommends and owns shares of Apple. It also owns shares of China Mobile. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.