Financial instruments and related items, which potentially subject the Company to concentrations of credit risk, consist primarily of cash, cash equivalents and trade receivables. The Company places its cash and temporary cash investments with high credit quality institutions. At times, such investments may be in excess of the FDIC insurance limit.

The Company's revenues earned from sale of products and services for the three months ended September 30, 2019 included 43%, 20%, and 19% (aggregate of 82%) from three customers of the Company's total revenues.

The Company's revenues earned from sale of products and services for the nine months ended September 30, 2019 included 34%, 23%, 16%, and 15% (aggregate of 88%) from four customers of the Company's total revenues.

The Company's revenues earned from sale of products and services for the three months ended September 30, 2018 included 24%, 11%, 27% and 26% (aggregate of 88%) from four customers of the Company's total revenues.

The Company's revenues earned from sale of products and services for the nine months ended September 30, 2018 included 20%, 21%, 20% and 18% (aggregate of 79%) from four customers of the Company's total revenues.

At September 30, 2019, one customer accounted for 100% of the Company’s total accounts receivable with an amount of $1,600, and three customers accounted for 44%, 17% and 32% (aggregate of 93%) of the Company's total accounts receivable at December 31, 2018.