What is the proper nlobjSearchColumn join for Estimate line items

Hello,

I am using a suitescript to retrieve quote/estimate information and I want the line items but  dont know what the search join is in order to retrieve the line items - can anyone help me?

columsn 0 - 4 are fine and retireve standard columns and a custom field. What should i put in the column 5 to retireve the amount for each line?

 var filters = new Array();    filters [0] = new nlobjSearchFilter('internalidnumber', null,  'equalto', '115095');  filters [1] = new nlobjSearchFilter('mainline',null,'is','F')    var columns = new Array();    columns[0] = new nlobjSearchColumn('tranid');  columns[1] = new nlobjSearchColumn('entitystatus');  columns[2] = new nlobjSearchColumn('entity');  columns[3] = new nlobjSearchColumn('internalid');  columns[4] = new nlobjSearchColumn('custbodyquote_prec_monthly_contr');  columns[5] = new nlobjSearchColumn('amount', item);