The model contains one compartment called C. There are three species called S1, S2 and S3 and two parameters called k1 and k2. Compartment C is 1-dimensional. The model contains two reactions defined as:

Reaction Rate
S1 + S2 → S3 k1 · S1 · S2 · C
S3 → S1 + S2 k2 · S3 · C

The model contains two events that assign values to species S2 and S1:

Trigger Delay Assignments
Event1 S1 < 0.65 S2 = 1
Event2 S3 > 1.2 S1 = 1

The initial conditions are as follows:

Value Units
Initial amount of S1 1.0 mole
Initial amount of S2 2.0 mole
Initial amount of S3 1.0 mole
Value of parameter k1 0.075 metre mole-1 second-1
Value of parameter k2 0.025 second-1
Length of compartment C 1 metre

The species values are given as amounts of substance to make it easier to use the model in a discrete stochastic simulator, but (as per usual SBML principles) their symbols represent their values in concentration units where they appear in expressions.