Synthetic shares are a simpler unleveraged variety of CFD's. They are derivatives, not a security, so their value depends on the value of the underlying instrument, i.e. the share price.
Synthetic Shares benefits
Zero swaps - No costs are charged for leaving a position open overnight
Dividends - If you buy Synthetic Shares, you are eligible to get dividends
Reduced market risks - Synthetic stocks are not leveraged, so there is no risk of losing more than you spent to open a position
quick settlement of transactions - the D + 0 cycle ensures settlement of the investment on the same day