Note 6. Warrants

We have certain warrants outstanding to purchase our common stock, at various prices, for the three months ended March 31, 2026 and 2025 is as follows:

(1) – Aggregate intrinsic value based on closing common stock price of $0.16 at March 31, 2026.

Warrants issued in Unit Offerings

During the three months ended March 31, 2026, we issued six-month stock purchase warrants to purchase an aggregate 599,416 shares of our common stock at $0.22 per share, and five-year stock purchase warrants to purchase an aggregate 599,416 shares of our common stock at $0.27 per share, in conjunction with the sale of stock to investors in our Unit Offerings (see Note 3). The relative fair value of the warrant component of the units sold to investors totaled $58,000. The Black-Scholes model was used to calculate relative fair value, further discounted by the beneficial conversion feature and the value of the common stock component.

We did not issue any warrants in conjunction with unit offerings in the three months ended  March 31, 2025.

Warrant Fair Value

We use the Black-Scholes option pricing model to determine the relative fair value of warrants issued in conjunction with debt instruments, common stock, and for services. With respect to debt instruments, relative fair value is amortized over the life of the warrant. The principal assumptions we used in applying the Black-Scholes model were as follows:

The risk-free interest rate is based on U.S. Treasury yields in effect at the time of grant. Expected volatilities are based on historical volatility of our common stock. The expected life in years is based on the contract term of the warrant.