As part of the reinforcing steel component. Again, this is where you drill down and you start breaking it up. It's part of reinforcing steel, you've got steel bars. You've got welded wire fabric, measured per pound or square foot and usually the bars are fabricated to the required lengths and shapes like commercial shops prior to delivery to a project. Also, usually estimated requests to these shops to provide quotations covering the supply and fabricating of all reinforcing for a given project. So here, you're going to be relying on the actual shop, quotations that you can then use within your pricing. Again, you'll be referring to your guidebooks here for the certain properties involved in reinforcing the bars. And here, you've got the bar number, the diameter, the area it would cover and the weight per pound. So, it gives you the key information you need to price this up. So, what affects the productivity in rebar-placing activities? So, rates vary with the following factors. So the size and length of the bars, the shape of the bars, the complexity of the structure. So, simple structures like walls are faster than complex structures like stairs. The distance and height a stair must be carried effects the price. The allowable tolerance in spacing bars extent of time required. So, we mentioned the ties earlier and also the skills of the workers. So the better the worker, the faster they'll be able to actually put in place the reinforcing steel bars. Let's look at the concrete component here. So the cost of concrete in a structure includes the cost of the aggregate, the cement, the water. And then lastly, the actual equipment used to mix all of it together, including any transportation and the placing of the concrete. So, all this comes into the pricing of concrete. Again, you have your guide books that can guide you the mix, the particular finest of the aggregate and the pounds and also the strength involved and this will apply to any particular scope of works or the project you'll be doing. It'll be different every time and this is just an example. Using your guide books, there'll be a lot more detail and a lot more information that you'll use applicable to that particular project that you're working on. Also, the outputs of the concrete mixers is important, that all comes into the pricing. And again, the guidance gives you the size of it, the range and the approximate output per cubic yards per hour you would get out of the mixes that mix the concrete together. So, what affects the productivity of concreting activities? So it varies with the location of aggregate piles and cement storage. So, that's transportation. The length of the haul and equipment used to haul the concrete. The conditions of the runways, the distribution of the placing area. There is always key to allow time for getting ready to start the pour, the cleaning up the mixes and all the buggies and for putting away tools and equipment after the pour is completed. So it's not always as simple as working out the time just to do the job, there's a lot more involved at the start and at the end as well. So what we've just covered there, a cost of materials. We looked at an example of a concrete wall. We looked at the formwork component, how you need bring that up to allow you to price it properly. We looked at reinforcing steel and the concrete.