The REITs with Risk Management portfolio combines Singapore REITs with Singapore Government Bonds (via the ABF Singapore Bond Index Fund). 

The REITs component in this portfolio also tracks the SGX's iEdge S-REIT Leaders index.

 Is there a minimum or maximum for the REITs component?

Your REITs with Risk Management portfolio will always have a REITs allocation of at least 50%. In other words, there is a minimum of 50% REITs for this portfolio. 

There is no maximum REITs allocation, i.e. your REITs allocation may even form 100% of your portfolio if market conditions are extremely favourable.